A geofence warrant is a court order that directs a technology company, most often Google, to identify every device that was inside a specified geographic area during a specified window of time. Instead of naming a suspect, investigators draw a shape on a map, pick a time range, and ask the company to search its location records for anyone who was there. Multiple federal courts have now held that this kind of search violates the Fourth Amendment, and Google has restructured its systems so it no longer holds the centralized location database that made the technique possible in the first place.
How the Search Actually Works
Phones generate location data constantly through GPS satellites, nearby Wi-Fi networks, and cell tower connections. Google combined all three signals into a product called Sensorvault, a centralized database that stored years of timestamped coordinates for hundreds of millions of accounts that had Location History turned on. When Maps wasn’t even open, the system was still logging where the phone went and how long it stayed.
To execute a geofence warrant, investigators defined a polygon using latitude and longitude, specified a time window, and served the warrant on Google. The company then ran a query against Sensorvault and returned the devices that were inside the zone during the period. The search was indiscriminate by design: everyone in the area came back, from the robbery suspect to the person buying coffee next door.
Google used a three-step disclosure process meant to limit how much personal information reached police at each stage:
- First, Google returned an anonymized list of numerical device identifiers with timestamped coordinates. No names or account details were attached.
- Second, investigators reviewed that list for movement patterns that looked relevant, such as a device arriving shortly before a crime and leaving shortly after. For a narrower subset of devices, police could ask for additional location points beyond the original zone or time window.
- Third, after narrowing the list further, investigators asked Google to unmask the remaining devices. Google then handed over subscriber names, email addresses, phone numbers, and other account details.
Courts have questioned whether this graduated process actually protects anyone, because the initial query at step one still rummages through the records of every account in the database to produce the list.
Is a Geofence Warrant Constitutional?
The Fourth Amendment requires that a warrant be supported by probable cause, describe with particularity the place to be searched and the things to be seized, and be issued by a neutral judge. A geofence warrant has trouble with all three.
The starting point is Carpenter v. United States, in which the Supreme Court held in 2018 that people have a legitimate expectation of privacy in their physical movements as captured through cell-site location information, and that the government generally needs a warrant to obtain those records. The Court rejected the argument that sharing data with a phone company extinguishes any privacy interest in it.1Supreme Court of the United States. Carpenter v. United States, No. 16-402 Carpenter involved one suspect’s records, but courts have extended its reasoning to geofence warrants, where the data is more detailed and the sweep is far wider.
The probable cause problem is straightforward. A traditional warrant says there is reason to believe a particular person committed a crime and that evidence will be found in a particular place. A geofence warrant says a crime happened somewhere and asks to search everyone’s location history to see who might have done it. That inversion has proved fatal in several cases.2Supreme Court of the United States. Google LLC Amicus Brief, Chatrie v. United States, No. 25-112
Particularity is the other weak point. A geofence drawn around a busy intersection at rush hour or a shopping center on a Saturday afternoon captures data from thousands of uninvolved people. Judges have increasingly treated oversized geofences as the modern equivalent of the general warrants the Fourth Amendment was written to forbid.3Harvard Law Review. Geofence Warrants and the Fourth Amendment
The Key Rulings
The clearest ruling came from the Fifth Circuit Court of Appeals in United States v. Smith. The court held that geofence warrants are “general warrants categorically prohibited by the Fourth Amendment.” Its reasoning: when Google runs a geofence query, it searches its entire Sensorvault, all 592 million accounts, to find devices in the target area, and that happens while law enforcement has “no idea who they are looking for, or whether the search will even turn up a result.” The court also rejected the argument that the three-step process cures the problem, because the constitutional violation occurs at step one and later narrowing cannot retroactively justify the initial dragnet.4United States Court of Appeals for the Fifth Circuit. United States v. Smith, No. 23-60321
In United States v. Chatrie, a federal district court in Virginia reached the same conclusion, becoming the first federal court to hold a geofence warrant unconstitutional for lack of particularized probable cause. Courts in Wisconsin and Colorado have quashed geofence warrants on similar grounds.2Supreme Court of the United States. Google LLC Amicus Brief, Chatrie v. United States, No. 25-112
Why the Evidence Still Gets Used
Here is the catch. In both Smith and Chatrie, the courts declared the warrants unconstitutional and then refused to suppress the evidence. They applied the good-faith exception to the exclusionary rule, reasoning that the officers were using a novel technique, had consulted with prosecutors, and had no clear precedent telling them it was illegal. Under that exception, evidence from an unconstitutional search can still be used at trial if the officers reasonably believed they were acting lawfully.4United States Court of Appeals for the Fifth Circuit. United States v. Smith, No. 23-60321
That cover is running out. Now that appellate and district courts have declared geofence warrants unconstitutional, officers can no longer claim ignorance of the rule. Future geofence searches face a much harder suppression fight. Google has filed an amicus brief urging the Supreme Court to take up Chatrie, which could settle the question nationally.
The Innocent-Bystander Problem
The practical criticism of geofence warrants is that they turn ordinary people into suspects for standing in the wrong place. Jorge Molina learned this firsthand. Police in Arizona arrested him after a geofence warrant linked a device tied to his Google account to a 2018 murder scene. An interrogator told him his phone placed him there “one hundred percent, without a doubt.” He spent six days in jail. It later came out that Molina had lent an old phone, still logged into his Google account, to his mother’s ex-boyfriend, who became the actual suspect. By then Molina had dropped out of school, lost his job and his car, and had his name published as the primary suspect across dozens of news outlets.
The case shows a flaw built into the technology. A device identifier is not a person. Phones get shared, sold, or left behind, and a single Google account can be active on several devices at once. Even when the right phone is matched to the right owner, being near a crime scene is not evidence of involvement, and most of the people inside a public geofence are commuters, shoppers, or neighbors.
Google’s Move to On-Device Storage
The landscape changed when Google announced it would stop storing location history in a centralized cloud database. Under the new system, Timeline data lives on the user’s device. If a user chooses to back it up to Google’s cloud, the backup is end-to-end encrypted, so neither Google nor anyone with legal authority over the company can read it.5Google. Updates to Location History and New Controls Coming Soon to Maps
This change effectively kills the traditional geofence warrant. If Google no longer holds a searchable database of user locations, it has nothing to produce in response to a broad area query. Law enforcement can still obtain a warrant for a specific person’s device and demand its contents, but that requires identifying the suspect first, which is exactly what the geofence warrant was designed to avoid.
The timing was not accidental. Google made the change as courts turned against geofence warrants and as the company faced pressure from privacy advocates and users. In 2020 alone, law enforcement served Google with more than 11,500 geofence warrants. Moving the data off its servers removed both the legal exposure and the engineering cost of responding to those requests.
What About Apple and Other Sources
Google dominated the geofence conversation because it was the only major company running a centralized, searchable location database at scale. Apple has never stored that kind of data. Its transparency report states plainly that “Apple does not have any data to provide in response to geofence warrants.”6Apple. About Apple’s Transparency Report
That does not make iPhone users invisible. Police can still get location information from cell carriers, from third-party apps that track location on their own servers, and from services like Uber or Snapchat that log GPS coordinates. The end of Sensorvault closes the single largest source of geofence data. It does not end location tracking.
Legislative Responses
A handful of states have passed laws restricting geofence or reverse-location searches. Utah requires a search warrant for any reverse-location request within the state and limits exceptions to situations involving an ongoing threat to public safety.7Congress.gov. Geofence Warrants and the Fourth Amendment Several other states have introduced similar bills, though many have stalled in committee. Most states still have no statute specifically addressing the issue.
At the federal level, the Fourth Amendment Is Not For Sale Act passed the House in the 118th Congress. The bill would bar law enforcement and intelligence agencies from buying location data and other personal records from third parties, require court orders before acquiring certain subscriber records, and extend privacy protections to data brokers that sit between tech companies and the government.8Congress.gov. Fourth Amendment Is Not For Sale Act, H.R. 4639 Its future is uncertain, but its progress reflects bipartisan concern about government access to commercially collected data.
Protecting Your Own Location Data
Google’s architectural shift has reduced the chance of being swept into a geofence query, but your phone still generates a lot of location data. A few steps can limit your exposure.
- Check whether Timeline is on. Open Google Maps, tap your profile picture, and select “Your Timeline.” From there you can review what is stored, turn Timeline off, or delete stored history.9Google Account Help. Manage Your Timeline Data
- Review cloud backups. Even with on-device storage, you may have opted to back up Timeline to Google’s cloud. The backup is end-to-end encrypted, but you can delete backups for individual devices or all devices through the cloud icon in the Timeline menu.10Google Maps Help. Manage Your Google Maps Timeline
- Audit third-party apps. Many apps request location permissions and store the data on their own servers, well outside Google’s ecosystem. Review which apps have location access in your phone’s settings and revoke it from anything that doesn’t need it.
- Understand the limits. Turning off Timeline does not stop your cell carrier from logging tower connections or prevent Wi-Fi networks from detecting your device. Full location invisibility requires turning the phone off. The realistic goal is reducing how many companies hold detailed, searchable records of your movements.
The rules around geofence warrants have shifted quickly. Courts are declaring them unconstitutional, Google has dismantled the database that made them possible at scale, and legislators are working on the remaining gaps. The underlying fact has not changed: your phone generates location data all day, and the law governing who can see it is still being written.