By Jordan Taylor, Law Clerk
Summary of Chatrie v. United States
On June 29, 2026, the Supreme Court decided a landmark Fourth Amendment case, Chatrie v. United States, holding again that an individual has a reasonable expectation of privacy in his cellphone location information. This means that police must get a warrant that meets all Fourth Amendment requirements, or operate under a valid warrant exception, to access this information.
In deciding this issue, the Court extended its previous decision in United States v. Carpenter, which granted Fourth Amendment protection to cell-site location information, to Location History information collected and stored by Google. Further, the Court refused to apply the third-party doctrine to Location History information shared with Google, finding that “a cell-phone user is not to be viewed as sharing private information with third parties – which then can be freely passed on to the government – just by doing the ordinary things cell phone users do.”
The Chatrie decision, like Carpenter, recognizes that cellphones are an “indispensable” part of modern life and provides a further layer of protection from government intrusion in the digital age. This article breaks down the decision and one of its most significant issues, the third-party doctrine.
Legal Issue
Whether the police conducted a Fourth Amendment search when they accessed Location History information collected by Google via a geofence warrant.
Fourth Amendment search = violation of a reasonable expectation of privacy that requires police to first get a warrant or operate under a valid warrant exception.
Location History information = time-stamped records of a person’s location collected by Google applications on their phone every two minutes. The phone’s location is drawn from “nearby Wi-Fi networks, Bluetooth beacons, and cell sites, as well as GPS and IP address information.” Location History must be turned on by the user, runs constantly in the background, and stops only if a user affirmatively turns it off. Like other information collected by Google, Location History is stored on the cloud but is accessible from a person’s device, which allows people to take advantage of the data to use maps, get recommendations, or receive updates about their commute, among many other things.
Geofence warrant = the specific type of warrant utilized by law enforcement when requesting Location History information from Google. The warrant specifies a timeframe and location and then asks Google to produce certain information about any devices that were located within that area at that time. As the Court stated, the warrant essentially asks Google: “Tell us, through cell-phone location data, who was there when a crime happened.” Over time, as the use of these warrants increased exponentially, Google developed a three-step process to handle the requests:
- Google first produces “anonymized location data for all cell phones within the geofence,” including each phone’s coordinates every two minutes or so, time stamps, accuracy, and source.
- Next, officials review the original data and “ask Google to provide additional information for a subset of still-anonymized users,” this time within a longer timeframe and both inside and outside of the geofence.
- Last, “officials demand the identities of a further subset of users,” and Google provides their “names, email addresses, and phone numbers.”
Decision of the Court
Yes, the police do conduct a Fourth Amendment search when they access Location History information collected by Google, as “an individual has a reasonable expectation of privacy in records about his cell phone’s location.” This is true regardless of the length of the time period at issue. Further, the third-party doctrine does not apply to cell-phone location information like Location History.
The Supreme Court did not decide whether the warrant utilized by police in this case was valid under the Fourth Amendment, instead sending that issue back to the Court of Appeals.
Precedent: United States v. Carpenter
The Court relied heavily on a precedent case, United States v. Carpenter, in reaching its decision in Chatrie. In Carpenter, the Court held that people have a reasonable expectation of privacy in their cell site location information (CSLI).
Cell-site location information = “time-stamped records generated each time a cell phone connects to a cell site.” This information is collected by wireless carriers like Verizon or AT&T and can be used to track a person’s location.
The Carpenter Court compared the use of CSLI to the use of a GPS tracking device placed on a vehicle which, in United States v. Jones, was held to be a Fourth Amendment search. Individuals “have a reasonable expectation of privacy in the whole of their physical movements.” Since CSLI allows for even more detailed tracking than a GPS, as people constantly carry their phones on them in both public and private spaces, the Court held that people also have a reasonable expectation of privacy in their location as recorded by CSLI.
Further, unlike the use of a GPS device, which requires advance planning on who or what to track, the use of CSLI can be done retrospectively to anyone. Thus, in Carpenter, the defendant’s Fourth Amendment rights were violated when the police accessed seven days’ worth of his CSLI without a warrant to pinpoint his location at the time of a robbery. The Chatrie Court compared CSLI to Location History information and found that the Fourth Amendment reasoning in Carpenter applied to Location History data.
- First, Location History information is even more detailed and accurate than CSLI, as it records every two-minutes and can pinpoint a person’s location “within around twenty meters, which is less than two percent of a mile.”
- Second, Location History information allows for retrospective tracking like CSLI, which means that law enforcement need not plan in advance who or what to track. When tracking via CSLI or Location History information, a person or location has essentially been “tailed every moment of every day.”
- Finally, and unlike CSLI, many people consider Location History information to be theirs, as they are aware of it and regularly use it to see where they’ve been, how far they’ve walked, what time they left a place, and so on. Thus, like photographs and emails, a user feels a sense of ownership over his Location History data and expects it to be kept private.
Ultimately, the Supreme Court held that an individual has a reasonable expectation of privacy in his Location History information collected by Google.
Third-Party Doctrine
This decision is significant in many respects, but its potential impacts on the third-party doctrine are the most obvious.
Third-party doctrine = principle that a person has no reasonable expectation of privacy in information voluntarily exposed or conveyed to third parties, developed in United States v. Miller (bank records) and Smith v. Maryland (numbers dialed).
In Chatrie, the government tried to argue that the third-party doctrine applied to Location History and therefore no search occurred when police accessed this information. The Court rejected the government’s argument, as it did in Carpenter, finding that Location History is not truly shared with a third party unlike bank deposit records or the numbers one dials on his telephone.
Cellphones are an “indispensable” part of modern life; almost everyone has one, and almost everyone carries one all the time, in both public and private. And while users technically do have a choice to turn on Location History, the Court emphasized how Google prompts users to turn the service on, how it warns that Android devices will not work as well if it is off, and how users may be unaware of the breadth of information recorded by the service and that the company may turn it over to the government.
Thus, the information is “not truly shared” with Google for purposes of the third-party doctrine. Further, even though people must affirmatively turn on Location History, unlike CSLI which is recorded by the mere act of carrying a phone, “[t]he point of carrying smartphones is to use what is on them. . . That is what has become a ‘pervasive and insistent’ – even ‘indispensable’ – ‘part of daily life.’” This includes Location History, which many people use as a personal journal to tell them where they’ve gone or where they might want to go in the future. And it includes our photos, emails, and documents; “private materials” that we send “to live on [a] company’s servers.”
In the modern world, nearly everything requires us to use our phones and, specifically, to use third-party apps to store our private information. With this reality in mind, the Court dealt a massive blow to the third-party doctrine, writing: “A cell-phone user is not to be viewed as sharing private information with third parties – which then can be freely passed on to the government – just by doing the ordinary things cell phone users do.”
Major Takeaway
The Chatrie decision held that individuals have a reasonable expectation of privacy in their cell phone location information. It is not entirely clear if this decision will affect the application of the third-party doctrine to other types of data existing on a person’s cell phone, but it is possible that future arguments will rely on Chatrie in seeking constitutional protection for sensitive digital information. And when police want to access cellphone location information, the rule is clear. To quote Chief Justice Roberts in Riley v. California: “get a warrant.”
* * *
