Regulating commercial location tracking has reached a turning point. Last year, we published our rubric for what comprehensive and protective location privacy laws should look like, outlining the baseline standards states should meet to shield individuals from pervasive location surveillance. Since then, state lawmakers across the country have begun responding to calls like these, with Connecticut, Maryland, New Jersey, Oregon, and Virginia enacting new consumer privacy restraints on an industry that profits off our physical movements.

Yet, even as these states move the ball forward to restrict location tracking, most of their laws leave significant gaps that still must be filled. Other states – and Congress – need to get into the game, too, and ensure protection of everyone.

Why Location Privacy Is Important

Imagine spending a couple of hours in a coffee shop, a friend's house, or a healthcare clinic, only to discover yourself under police investigation because your cell phone’s location data exposed your presence there.

This is the reality of geofence warrants for location data, the controversial surveillance technique recently scrutinized by the U.S. Supreme Court in Chatrie v. United States. Through geofencing, tech companies and law enforcement can map everyone who was present within a specific area over a certain window of time, inverting standard constitutional protections by turning every innocent bystander into a potential suspect. While the Supreme Court's ruling in Chatrie established that accessing location data via geofencing constitutes a Fourth Amendment search requiring constitutional protections, law enforcement demands via these warrants are only part of the problem. That same geolocation tracking is used by commercial data brokers operating in a largely unregulated market. These brokers regularly harvest, aggregate, and sell physical location data to anyone with a credit card (including government agencies, which are among their regular clients). Especially for individuals seeking reproductive or gender-affirming care, attending a protest, or visiting an immigration law clinic, this pervasive commercial location surveillance represents an immediate threat.

In Part 1 of this series, we urged lawmakers to protect people from the growing harms of location tracking tools across all areas of public life. The real-world consequences of this unregulated market impact us all. An anti-LGBTQ+ advocacy group spent millions of dollars buying app location data to track priests across multiple dioceses and used app-harvested location data to “out” a priest after purchasing his Grindr location signals. Privacy advocates posing as private investigators gained access to Locate X, a location-tracking tool developed by Babel Street, and demonstrated how the tool tracked a device traveling from Alabama, where abortion is banned, to an abortion clinic in Florida, where access is less restricted. Data brokers like Near Intelligence have sold precise location data of reproductive health clinic visitors directly to political groups. Location data has been used to locate U.S. military personnel in war zones. Law enforcement and private entities have also weaponized location tracking directly against political protesters: surveillance contractors and authorities have utilized location data derived from real-time bidding ad networks to track individuals attending demonstrations.

The unregulated sharing of location data has created an ever-larger funnel for data brokers to capture and monetize our movements. For example, a recent EFF investigation identified several advertising Software Development Kits (SDKs) in Android apps that by default collect and share users' location data whenever app-level location permissions are granted. These advertising libraries automatically feed users' location data into ad systems that location data brokers have used to track people. Because defaults direct real-world outcomes, app developers who fail to carefully scrutinize the third-party SDKs they use, and disable unnecessary data collection, could inadvertently expose their users’ movements to commercial data brokers.

State Legislative Progress

Last year, we outlined six essential core principles that any meaningful location privacy law must contain:

• Strong definitions,
• Clear rules,
• Affirmation that all precise geolocation data is sensitive,
• Empowerment of consumers through a strong private right of action,
• Prohibition of “pay-for-privacy” schemes, and
• Transparency through clear privacy policies.

While the bills we highlighted from California, Illinois, and Massachusetts are yet to pass into law, a new wave of state location privacy legislation has taken effect across Connecticut, Maryland, New Jersey, Oregon, and Virginia.

These five laws represent progress, and share two strong features.  First, all five of these states ban the sale of precise geolocation data. This will remove a strong incentive to collect and store this information in the first place. Other types of privacy laws have likewise banned the sale of sensitive types of data, like the Illinois Biometric Privacy Act (BIPA), which bans the sale of biometric information such as face scans.

Second, all five states broadly define the protected data to include all kinds of locations across the board within a particular distance of a person or their device, rather than protecting just narrowly-defined “sensitive” locations. This all-locations protection sets these laws apart from California’s A.B. 45 of 2025, for example, which only restricts location tracking within 1,850 feet of a family planning center. Protecting location data only near specific locations (like health care facilities) is insufficient: if an individual travels across state lines for care, a data broker can still track their route right up to the boundary of a protected zone and pick it up immediately upon departure, making it easy to infer their destination.

These five laws vary regarding whether, on top of the ban on sale, they require consent and/or minimization for other kinds of processing of precise geolocation data. Maryland’s Online Data Privacy Act (MODPA) requires strict minimization. Specifically, a data controller cannot collect, use, store, or disclose a consumer’s precise geolocation data (or other sensitive data) unless doing so is “strictly necessary to provide or maintain a specific product or service requested by [that] consumer.” Minimization is an important privacy protection because it imposes a duty where it belongs: on the company processing a person’s data. Maryland requires doubly strong minimization. First, the data processing must be “strictly necessary,” and not just “necessary,” or even worse, “reasonably necessary.” Second, the necessity of data processing must be tied to what the particular consumer requested, and not to what a generic customer might hypothetically have thought was reasonable, or the company’s own purposes, or whatever the company buried in its own long-winded legalese.

Connecticut requires both strong consent and weak minimization. Specifically, it forbids a data controller from collecting, using, storing, or disclosing a consumer’s precise geolocation data (among other sensitive data) “without first obtaining [that] consumer’s consent”. Connecticut has a strong definition of consent: “a clear affirmative act signifying freely given, specific, informed and unambiguous agreement,” which is absent from “agreement obtained through the use of dark patterns.” On top of this strong consent, Connecticut also requires a weak form of minimization: the data processing must be “reasonably necessary in relation to the purposes for which such sensitive data are processed”. But this does not weaken Connecticut’s strong consent rule.

New Jersey requires consent to collect, use, store, or disclose a person’s precise geolocation data (and other sensitive data).

Virginia protects location data with both minimization and consent, but only for one kind of people (known children) and only for one kind of data processing (collection). Under Virginia’s minimization rule, a data controller cannot collect such data from such people unless doing so “is reasonably necessary for the controller to provide an online service,” and in such cases, “only … for the time necessary” to do so. This would be a much stronger rule if the authors struck the modifier “reasonably” before the word “necessary,” or better yet, substituted the modifier “strictly.”

Beyond its ban on sale, Oregon does not limit the processing of precise geolocation data.

Gaps in Current Legislation

While these enacted bills mark steps in the right direction, major loopholes remain that leave users vulnerable.

The Enforcement Void: Why Every Law Needs a Private Right of Action

A privacy law without a Private Right of Action is a law "without teeth”.

None of these five state statutes expressly empower consumers to directly sue companies that violate their location privacy rights. Relying exclusively on state Attorneys General or specialized regulatory agencies creates a critical bottleneck, since no regulatory agency possesses the staffing or budget required to investigate every data privacy violation. Additionally, government enforcement priorities shift across administrations, leaving enforcement vulnerable to political pressures and corporate lobbying.

The best way to ensure effective enforcement is a free-standing, explicit Private Right of Action written directly into the privacy statute. Some legislative privacy proposals instead attempt to provide remedies by piggybacking on state laws against unfair, deceptive, or abusive practices (UDAP). But this is often hit-or-miss depending on each state’s specific UDAP law, including who must have what kind of injury to have standing to bring a private action, and the scope of remedies. For instance, while Maryland’s MODPA provides that a violation of the statute constitutes a banned UDAP, it appears that the new law’s enforcement mechanics were drafted in a way that provides only government enforcement through the Attorney General’s Consumer Protection Division, rather than granting consumers a private right of action.

Any a private right of action should come complete with statutory liquidated damages to remedy non-economic harm, and prohibitions against mandatory arbitration. This ensures that compliance isn't optional. Until corporate bad actors face direct accountability from the very people whose personal location data they unlawfully exploit, state privacy laws will rely on overworked regulators to police an industry that profits off our every move.

The "Pay-for-Privacy" Trap

Privacy is a fundamental right, not a luxury tier. So EFF opposes pay-for-privacy schemes, in which companies charge a higher price to people who exercise their privacy rights. To prevent these schemes, data privacy legislation must prohibit companies from retaliating against consumers who exercise their statutory privacy rights, including by charging a higher price. For example, if a statute bars a company from processing a person’s data absent their consent, and that person withholds consent, the statute must bar the company from responding by charging a higher price.

Unfortunately, all three of these states that require consent to process precise geolocation information (Connecticut, New Jersey, and Virginia) have only weakly limited pay-for-privacy schemes. While all three prohibit discrimination against customers who withhold consent, all three also have a wide loophole: for discount programs. To make matters worse, none of these three states prevent the discount programs from selling customer data to third parties. But people should not have to surrender their data privacy to join a discount club for regular customers. Thus, the far better approach is to eschew this loophole, as in the ban on pay-for-privacy in last year’s location data privacy bills in Illinois and Massachusetts.

These exceptions allow companies to charge higher prices or downgrade service quality for users who exercise their privacy rights. In practice, this converts privacy into a privilege for those who can afford it, forcing economically vulnerable communities to trade away their sensitive location movements in exchange for essential discounts or services.

Dark Patterns

Any law that requires consent also needs to ban company techniques that subvert consent. These are often called dark patterns, predatory design, and manipulative user interface (UI/UX) practices.

Connecticut’s definition of “consent” excludes “dark patterns,” as noted above. That state defines dark patterns as “a user interface designed or manipulated with the substantial effect of subverting or impairing user autonomy, decision-making, or choice,” including any practice that the FTC refers to as a dark pattern. Other consent-based privacy rules must do so, too.

Conclusion

The recent wave of state legislation demonstrates that momentum is building against location surveillance. However, state leaders must go further.

To build privacy protections that withstand corporate workaround attempts, future bills must apply to all locations universally, give individuals the legal standing to enforce their own rights in court, and fully prohibit pay-for-privacy. Until comprehensive data privacy legislation with real teeth is enacted nationwide, users can consult EFF's Surveillance Self-Defense Guide to learn practical steps for reducing location tracking on their personal devices.

You have an expectation of privacy in location data that reveals your movements in the physical world, and even short-term surveillance of these movements is a search subject to the Fourth Amendment, the U.S. Supreme Court ruled today in Chatrie v. United States.  

The case involved geofence warrants, a form of dragnet surveillance police have used to vacuum up location data from electronic devices of people who happen to be in the vicinity of a crime. EFF had joined the American Civil Liberties Union, the ACLU of Virginia, and the Center on Privacy & Technology at Georgetown Law in filing an amicus brief in the case. 

JOIN EFF

The decision in Chatrie is important: It is the first digital surveillance decision by the Court since its landmark 2018 ruling Carpenter v. United States, which involved prolonged tracking of people’s movements using cell phone location data. The new case expands that ruling by confirming that even shorter-term surveillance of location data can constitute a search because it can still reveal “private matters,” including “a wealth of detail about a person’s familial, political, professional, religious, and sexual associations.”  

The case is also important because the Court also recognized the records generated by the apps on a user’s phone—records we necessarily share with third-party tech company—are a user’s “own” and require Fourth Amendment protection. This is true, regardless of whether those records are “emails, documents, photographs, [ ] calendars” or location data. This will likely have broad implications for data generated by other apps on our phones, even if we click “agree” to sharing that data with third-party tech companies.  

Geofence warrants don’t name a suspect or a specific individual or device the way typical warrants do. Instead, they compel companies—almost always Google—to provide information on every electronic device in a given area during a given time period. This creates a high risk of suspicion falling on innocent people and can reveal sensitive and private information about where individuals have traveled in the past. 

Geofence warrants are the digital equivalent of police going person to person, home to home, without suspicion that any device holder has a connection to a crime. This turns innocent bystanders into suspects, just for being in the wrong place at the wrong time.  

In Chatrie, a 2019 geofence warrant compelled Google to search the accounts of all its hundreds of millions of users to see if any one of them was within a radius police drew around a Northern Virginia crime scene. This area amounted to several football fields in size and encompassed numerous homes, businesses, and a church. 

A federal district court in Virginia in 2022 held that the geofence warrant plainly violated  the Fourth Amendment. If the police want to get information on every device in the area, they must also establish probable cause to search every person in the area, the court said. The judge noted the government lacked particularized probable cause as to every individual within the geofence, which swept up innocent people and covered over 70,000 square meters in a busy area. 

The decision set an important precedent in finding the warrant overbroad and unconstitutional and was later followed by a 2024 federal Fifth Circuit Court of Appeals ruling holding that geofence warrants are “categorically prohibited by the Fourth Amendment.” However, the Chatrie lower court allowed the government to use the evidence it obtained because it relied on the warrant in “good faith.” A much divided en banc panel of the U.S. Court of Appeals for the Fourth Circuit in 2025 affirmed this “good faith” finding in the lower court’s opinion. 

Google in 2023 announced changes to how it stores location data, with the effect of eventually making it impossible for the company to respond to geofence warrants. Since July 2025, mass geofence searches of Google users’ location data have not been possible.  

However, Google is not the only company collecting location data, nor the only way for police to access mass amounts of data on people with no connection to a crime. As we’ve written about extensively, data brokers collect and aggregate location data from many different apps on our phones and provide that data to police. And police can use “cell tower dump” warrants to get access to data on everyone within range of specific cell towers. Suspicionless searches like these drag a net through vast swaths of information in hopes of identifying previously unknown suspects—ensnaring innocent bystanders along the way. 

Chatrie could have wide-ranging implications beyond location data as well. The Supreme Court affirmed that app data is subject to the Fourth Amendment, because users “reasonably view” it as their own and reasonably expect it “to be shielded from the ‘inquisitive eyes’ of the government.” Justice Gorsuch, in an opinion concurring in the judgment, called location data a user’s “personal property,” no different from myriad other “effects” explicitly protected by the text of the Fourth Amendment.  As the Court concluded, “the point of carrying smartphones is to use what is on them,” so the Fourth Amendment has to protect more than just location data generated by the act of carrying the phone itself. 

The Court ultimately did not decide whether the particular warrant at issue in Chatrie was “reasonable” or whether the “good faith” doctrine applied. The case now heads back to the Fourth Circuit Court of Appeals to address these questions.  

But regardless of how the Fourth Circuit rules on remand, this Chatrie opinion will shape how lower courts address police access to location and other data going forward. We look forward to citing Chatrie to press future courts to recognize broad Fourth Amendment protections for user data.

We've all had the unsettling experience of seeing an ad online that reveals just how much advertisers know about our lives. You're right to be disturbed. Those very same online ad systems have been used by the government to warrantlessly track peoples' locations, new reporting has confirmed.

For years, the internet advertising industry has been sucking up our data, including our location data, to serve us "more relevant ads." At the same time, we know that federal law enforcement agencies have been buying up our location data from shady data brokers that most people have never heard of.

Now, a new report gives us direct evidence that Customs and Border Protection (CBP) has used location data taken from the internet advertising ecosystem to track phones. In a document uncovered by 404 Media, CBP admits what we’ve been saying for years: The technical systems powering creepy targeted ads also allow federal agencies to track your location.

The document acknowledges that a program by the agency to use "commercially available marketing location data" for surveillance drew from the process used to select the targeted ads shown to you on nearly every website and app you visit. In this blog post, we'll tell you what this process is, how it can and is being used for state surveillance, and what can be done about it—by individuals, by lawmakers, and by the tech companies that enable these abuses.

Advertising Surveillance Enables Government Surveillance

The online advertising industry has built a massive surveillance machine, and the government can co-opt it to spy on us. 

In the absence of strong privacy laws, surveillance-based advertising has become the norm online. Companies track our online and offline activity, then share it with ad tech companies and data brokers to help target ads. Law enforcement agencies take advantage of this advertising system to buy information about us that they would normally need a warrant for, like location data. They rely on the multi-billion-dollar data broker industry to buy location data harvested from people’s smartphones.

We’ve known for years that location data brokers are one part of federal law enforcement's massive surveillance arsenal, including immigration enforcement agencies like CBP and Immigration and Customs Enforcement (ICE). ICE, CBP and the FBI have purchased location data from the data broker Venntell and used it to identify immigrants who were later arrested. Last year, ICE purchased a spy tool called Webloc that gathers the locations of millions of phones and makes it easy to search for phones within specific geographic areas over a period of time. Webloc also allows them to filter location data by the unique advertising IDs that Apple and Google assign to our phones.

But a document recently obtained by 404 Media is the first time CBP has acknowledged the location data it buys is partially sourced from the system powering nearly every ad you see online: real-time bidding (RTB). As CBP puts it, “RTB-sourced location data is recorded when an advertisement is served.” 

Even though this document is about a 2019-2021 pilot use of this data, CBP and other federal agencies have continued to purchase and use commercially obtained location data. ICE has purchased location tracking tools since then and recently requested information on “Ad Tech” tools it could use for investigations. 

The CBP document acknowledges two sources of location data that it relies on: software development kits (SDKs) and RTB, both methods of location-tracking that EFF has written about before. Apps for weather, navigation, dating, fitness, and “family safety” often request location permissions to enable key features. But once an app has access to your location, it could share it with data brokers directly through SDKs or indirectly (and often without the app developers' knowledge) through RTB. Data brokers can collect location data from SDKs that they pay developers to put in their apps. When relying on RTB, data brokers don’t need any direct relationship with the apps and websites they’re collecting location data from. RTB is facilitated by ad companies that are already plugged into most websites and apps. 

Donate to Support EFF's Work

Your donations empower EFF to do even more.

How Real-Time Bidding Works

RTB is the process by which most websites and apps auction off their ad space. Unfortunately, the milliseconds-long auctions that determine which ads you see also expose your information, including location data, to thousands of companies a day. At a high-level, here’s how RTB works:

1. The moment you visit a website or app with ad space, it asks an ad tech company to determine which ads to display for you. 
2. This ad tech company packages all the information they can gather about you into a “bid request” and broadcasts it to thousands of potential advertisers. 
3. The bid request may contain information like your unique advertising ID, your GPS coordinates, IP address, device details, inferred interests, demographic information, and the app or website you’re visiting. The information in bid requests is called “bidstream data” and typically includes identifiers that can be linked to real people. 
4. Advertisers use the personal information in each bid request, along with data profiles they’ve built about you over time, to decide whether to bid on the ad space. 
5. The highest bidder gets to display an ad for you, but advertisers (or the adtech companies that represent them) can collect your bidstream data regardless of whether or not they bid on the ad space.   

A key vulnerability of real-time bidding is that while only one advertiser wins the auction, all participants receive data about the person who would see their ad. As a result, anyone posing as an ad buyer can access a stream of sensitive data about billions of individuals a day. Data brokers have taken advantage of this vulnerability to harvest data at a staggering scale. For example, the FTC found that location data broker Mobilewalla collected data on over a billion people, with an estimated 60% sourced from RTB auctions. Leaked data from another location data broker, Gravy Analytics, referenced thousands of apps, including Microsoft apps, Candy Crush, Tinder, Grindr, MyFitnessPal, pregnancy trackers and religious-focused apps. When confronted, several of these apps’ developers said they had never heard of Gravy Analytics. 

As Venntel, one of the location data brokers that has sold to ICE, puts it, “Commercially available bidstream data from the advertising ecosystem has long been one of the most comprehensive sources of real-time location and device data available.” But the privacy harms of RTB are not just a matter of misuse by individual data brokers. RTB auctions broadcast the average person’s data to thousands of companies, hundreds of times per day, with no oversight of how this information is ultimately exploited. Once your information is broadcast through RTB, it’s almost impossible to know who receives it or control how it’s used. 

What You Can Do To Protect Yourself

Revelations about the government's exploitation of this location data shows how dangerous online tracking has become, but we’re not powerless. Here are two basic steps you can take to better protect your location data:

1. Disable your mobile advertising ID (see instructions for iPhone/Android). Apple and Google assign unique advertising IDs to each of their phones. Location data brokers use these advertising IDs to stitch together the information they collect about you from different apps. 
2. Review apps you’ve granted location permissions to. Apps that have access to your location could share it with other companies, so make sure you’re only granting location permission to apps that really need it in order to function. If you can’t disable location access completely for an app, limit it to only when you have the app open or only approximate location instead of precise location. 

For more tips, check out EFF’s guide to protecting yourself from mobile-device based location tracking. Keep in mind that the security plan that’s best for you will vary in different situations. For example, you may want to take stronger steps to protect your location data when traveling to a sensitive location, like a protest. 

What Tech Companies and Lawmakers Must Do

Legislators and tech companies must act so that individuals don’t bear the burden of defending their data every time they use the internet.

Ad tech companies must reckon with their role in warrantless government surveillance, among other privacy harms. The systems they built for targeted advertising are actively used to track people’s location. The best way to prevent online ads from fueling surveillance is to stop targeting ads based on detailed behavioral profiles. Ads can still be targeted contextually—based on the content people are viewing—without collecting or exposing their sensitive personal information. Short of moving to contextual advertising, tech companies can limit the use of their systems for government location tracking by:

• Stopping the use of precise location data for targeted advertising. Ad tech companies facilitating ad auctions can and should remove precise location data from bid requests. Ads can be targeted based on people’s coarse location, like the city they’re in, without giving data brokers people’s exact GPS coordinates. Precise location data can reveal where we work, where we live, who we meet, where we protest, where we worship, and more. Broadcasting it to thousands of companies a day through RTB is dangerous.
• Removing advertising IDs from devices, or at minimum, disabling them by default. Advertising IDs have become a linchpin of the data broker economy and are actively used by law enforcement to track people’s location. Advertising IDs were added to phones in 2012 to let companies track you, and removing them is not a far-fetched idea. When Apple forced apps to request access to people’s advertising IDs starting in 2021 (if you have an iPhone you’ve probably seen the "Ask App Not to Track" pop-ups), 96% of U.S. users opted out, essentially disabling advertising IDs on most iOS devices. One study found that iPhone users were less likely to be victims of financial fraud after Apple implemented this change. Google should follow Apple’s lead and disable advertising IDs by default.

Lawmakers also need to step up to protect their constituents' privacy. We need strong, federal privacy laws to stop companies from spying on us and selling our personal information. EFF advocates for data privacy legislation with teeth and a ban on ad targeting based on online behavioral profiles, as it creates a financial incentive for companies to track our every move.

Legislators can and must also close the "data broker loophole" on the Fourth Amendment. Instead of obtaining a warrant signed by a judge, law enforcement agencies can just buy location data from private brokers to find out where you've been. Last year, Montana became the first state in the U.S. to pass a law blocking the government from buying sensitive data it would otherwise need a warrant to obtain. And in 2024, Senator Ron Wyden's EFF-endorsed Fourth Amendment is Not for Sale Act passed the House before dying in the Senate. Others should follow suit to stop this end-run around constitutional protections.

Online behavioral advertising isn’t just creepy–it’s dangerous. It's wrong that our personal information is being silently harvested, bought by shadow-y data brokers, and sold to anyone who wants to invade our privacy. This latest revelation of warrantless government surveillance should serve as a frightening wakeup call of how dangerous online behavioral advertising  has become.

Donate to Support EFF's Work

Your donations empower EFF to do even more.