by Richard Resch

The Supreme Court of the United States held that police officers conducted a Fourth Amendment search when they acquired a criminal suspect’s Google Location History data through a geofence warrant, concluding that individuals maintain a reasonable expectation of privacy in records documenting their cellphone’s whereabouts. Justice Kagan delivered the opinion for a five-Justice majority, joined by Chief Justice Roberts and Justices Sotomayor, Kavanaugh, and Jackson. The Court determined that the privacy principles established in Carpenter v. United States, 585 U.S. 296 (2018), which recognized Fourth Amendment protections for cell-site location information (“CSLI”), applied with equal or greater force to Google’s Location History service. The Court rejected the Government’s two principal arguments: (1) that two hours of location data fell below any constitutional threshold and (2) that the third-party doctrine stripped the defendant of protection because he voluntarily enabled Location History. Having established that a search occurred, the Court declined to address whether the geofence warrant satisfied the Fourth Amendment’s probable cause and particularity requirements, remanding that question to the Fourth Circuit for resolution in the first instance.

Justice Jackson, joined by Justice Sotomayor, filed a concurrence agreeing that a search occurred but concluding that Steps 2 and 3 of the warrant failed to satisfy the Fourth Amendment for lack of adequate magisterial oversight. Justice Gorsuch concurred in the judgment only, reaching the same result through a property-based analysis based on the Fourth Amendment’s text rather than the reasonable-expectation-of-privacy framework derived from Katz v. United States, 389 U.S. 347 (1967). Justice Alito dissented, joined by Justice Thomas as to Part I and by Justice Barrett as to Parts II–B, II–C–1, and II–C–2, contending that the majority improperly extended Carpenter beyond its self-imposed limits. Justice Barrett filed a separate dissent.

Background

On May 20, 2019, a man robbed a credit union in Midlothian, Virginia, brandishing a firearm and fleeing on foot with $195,000. Through witness interviews and surveillance-camera footage, officers learned that the robber had walked toward the credit union from a nearby church while appearing to talk on a cellphone, but they could not identify him. On June 14, officers applied to a Virginia magistrate for a geofence warrant directed to Google, seeking cellphone location data collected through Google’s Location History service for all devices present within a 150-meter radius of the credit union near the time of the robbery.

The warrant described a three-step process. At Step 1, Google would produce anonymized location data for all cellphones within the geofence during the hour surrounding the robbery. At Step 2, officers would “attempt to narrow down” the device list by comparing the time-stamped location coordinates against known time and location information specific to the crime. For that narrowed list, Google would provide additional anonymized data over an expanded two-hour window, including locations outside the geofence. At Step 3, officers would again “attempt to narrow down” the list by comparing the additional travel and time information against known crime-specific information, and Google would disclose identifying information, including names and phone numbers, for each user on the final list. The magistrate issued the warrant. Google returned anonymized data for 19 users at Step 1. After officers narrowed the list, Google returned expanded anonymized data for nine users at Step 2 and identifying information for three users at Step 3. One was petitioner Okello Chatrie, whose data showed he entered the geofenced area about 10 minutes before the robbery and moved toward a residential neighborhood afterward. A federal grand jury charged Chatrie with robbery and related firearms offenses.

Chatrie moved to suppress the Location History evidence. The U.S. District Court for the Eastern District of Virginia found that the geofence warrant “plainly violates the rights enshrined in [the Fourth] Amendment” but denied the motion under the good-faith exception to the exclusionary rule. A divided Fourth Circuit panel affirmed on different reasoning, holding that no Fourth Amendment search occurred because Chatrie “did not have a reasonable expectation of privacy in two hours’ worth of Location History data voluntarily exposed to Google.” After granting rehearing en banc, the Fourth Circuit affirmed in a one-sentence per curiam opinion, with the court dividing evenly, seven to seven, on whether a search had occurred. The Supreme Court granted certiorari solely on the question whether police violated the Fourth Amendment in obtaining Chatrie’s location data.

Analysis

The Court divided the Fourth Amendment inquiry into two questions: (1) whether police conducted a search by obtaining Chatrie’s location data from Google and (2) whether the geofence warrant made that search reasonable. The majority resolved the former question and remanded the latter.

The Court began its analysis by discussing the principles governing a Fourth Amendment “search.” It observed that the Amendment’s “basic purpose” is “to safeguard the privacy and security of individuals against arbitrary invasions by governmental officials.” Carpenter (quoting Camara v. Municipal Court of City and County of San Francisco, 387 U.S. 523 (1967)). While early search doctrine focused on physical intrusions upon private property, the Supreme Court in Katz recognized that “the Fourth Amendment protects people, not places.” Under the analytical framework since Katz, a governmental intrusion upon an expectation of privacy that “society is prepared to recognize as reasonable” qualifies as a search for Fourth Amendment purposes. Carpenter. These expectations are measured against “guideposts” tracing to the Amendment’s origins, including the commitment to securing “the privacies of life” against “arbitrary power” and placing “obstacles in the way of a too permeating police surveillance,” the Court explained. Boyd v. United States, 116 U.S. 616 (1886); United States v. Di Re, 332 U.S. 581 (1948).

The Carpenter Precedent

The Court based its search analysis on Carpenter, where the Supreme Court had held that obtaining CSLI from a wireless carrier constitutes a Fourth Amendment search. In Carpenter, police investigating a series of robberies ordered a carrier to produce seven days of a suspect’s CSLI without obtaining a warrant. The Carpenter Court approvingly cited five Justices’ agreement in United States v. Jones, 565 U.S. 400 (2012), that GPS-based tracking of a vehicle implicated Fourth Amendment privacy interests because “individuals have a reasonable expectation of privacy in the whole of their physical movements.” Carpenter. Before the digital age, sustained surveillance of a suspect had been “difficult and costly and therefore rarely undertaken,” and society’s expectation was that law enforcement agents simply “could not” secretly catalog a person’s every movement. Id.

The Carpenter Court explained that CSLI intensified these concerns because a cellphone “tracks nearly exactly the movements of its owner,” following him “into private residences, doctor’s offices, political headquarters, and other potentially revealing locales.” The tracking capacity afforded by CSLI “runs against everyone” and “travel[s] back in time,” enabling retrospective surveillance with “just the click of a button.” Thus, Carpenter concluded that government access to these records “invaded Carpenter’s reasonable expectation of privacy in the whole of his physical movements.”

CSLI and Location History Compared

Turning to the surveillance technology at issue in the present case, the Court determined that the parallels between CSLI and Location History “practically leap off the page.” Every factor supporting the search finding in Carpenter applied “as well or better” to Location History, the Court reasoned. Three principal grounds supported this conclusion.

First, Location History provides a far more granular picture of a person’s movements, according to the Court. Whereas CSLI could identify Carpenter’s position only within sectors “ranging from one-eighth to four square miles,” Location History placed Chatrie within approximately 20 meters. CSLI logged Carpenter’s location an average of 101 times daily. Location History commonly records a cellphone’s position every two minutes, producing approximately 720 entries per day. Location History can also estimate elevation, revealing which floor of a building a user occupies.

Second, Location History likewise enables the same kind of effortless, retrospective surveillance that troubled the Carpenter Court. Law enforcement need not decide in advance whom to follow or which sites to monitor. The Court noted that Location History makes possible the “tireless and absolute surveillance” of any number of people in any number of places, a capability unimaginable in earlier generations of law enforcement.

Third, the Court determined that Location History implicates privacy interests even more acutely than CSLI because the data is “more the individual’s own.” Most cellphone users are unaware of CSLI records and would never seek to retrieve them. In contrast, Google users regularly consult Location History for what functions as a personal journal of their movements, using it to recall restaurants visited or retrace vacation routes. In this respect, the Court reasoned that Location History resembles other private materials stored on Google’s servers, such as emails, photographs, and calendars, that “a user reasonably views as his own” and expects to be shielded from the “inquisitive eyes” of the government. Carpenter.

Rejection of a Duration-Based Threshold

The Government argued that the two hours of location data at issue fell within a zone free from Fourth Amendment scrutiny. Because Carpenter had expressly reserved the question whether a “limited period” of location data might be obtained without constitutional consequence, the Government urged the Court to recognize a grace period during which no warrant would be required.

The Court rejected this position. It first disputed the premise that brief location monitoring cannot reveal private information, quoting Jones that “even short-term monitoring” of a person’s movements can expose “a wealth of detail about [his] familial, political, professional, religious, and sexual associations.” The Court stated that trips to “the psychiatrist, the plastic surgeon, the abortion clinic, [or] the criminal defense attorney” are “indisputably private,” and even two hours of Location History allows officers to identify who appears at particular sites or events.

Additionally, Fourth Amendment protections are not triggered “only once an intrusion ‘goes too far,’” the Court explained. Pennsylvania Coal Co. v. Mahon, 260 U.S. 393 (1922). Where the Amendment applies, it applies “regardless of ‘the quality or quantity of information’ the government obtains.” Kyllo v. United States, 533 U.S. 27 (2001). The Amendment “makes ‘no exception’ for the officer who barely cracks open the front door and sees nothing but the nonintimate rug on the vestibule floor.” Id. The same principle governed Katz, which involved only 18 minutes of recordings. A duration-based threshold would also generate unmanageable line-drawing difficulties, the Court cautioned. For example, at what point does a non-search become a search, how often would the clock reset, and would concurrent investigations effectively double the permissible surveillance window?

The Court distinguished United States v. Knotts, 460 U.S. 276 (1983), in which police use of a beeper to assist a vehicular tail did not implicate the Fourth Amendment. Knotts itself warned that “different constitutional principles” could apply as surveillance technology advanced. Five Justices in Jones found that they did when confronted with a GPS device, and Carpenter explained that Knotts addressed only “the rudimentary tracking facilitated by the beeper.” The Court reasoned that Knotts was further inapposite because that surveillance was confined to “public thoroughfares,” whereas Location History reveals movement into “private residences, doctor’s offices, [and] political headquarters.” Carpenter.

The Third-Party Doctrine

The Government separately invoked the third-party doctrine, arguing that Chatrie forfeited his privacy expectations by authorizing Google to collect his location information. That doctrine traces to United States v. Miller, 425 U.S. 435 (1976), and Smith v. Maryland, 442 U.S. 735 (1979). Miller reasoned that a depositor who “voluntarily conveyed” financial information to a bank had “take[n] the risk” that the institution would provide it to the government; Smith applied the same reasoning to telephone numbers dialed through a landline.

The Court observed that Carpenter had already refused to extend the third-party doctrine to CSLI and found “no good reason” to reach a different result for Location History. Carpenter distinguished CSLI from the records at issue in Miller and Smith in two respects. First, the “nature” of CSLI was incomparably “revealing” compared to telephone numbers and bank records. Second, cellphone location information was “not truly ‘shared’ as one normally understands the term” given that cellphones are “indispensable to participation in modern society.” The Court concluded that both features apply with equal or greater force to Location History, which is more precise than CSLI and which users reasonably understand as their own “even though stored on Google’s servers.”

The Government contended that enabling Location History, unlike generating CSLI, involves a voluntary choice, noting that only about one-third of Google accountholders had activated the service. The Court was unpersuaded. Google repeatedly prompts users to activate Location History, sometimes warning that devices will not “work correctly” without it, while failing to disclose how frequently or precisely it records location data or how that information might reach law enforcement. An “app-by-app, feature-by-feature” approach to Fourth Amendment protection “misapprehends the very nature of modern cell-phone use,” because virtually every smartphone function requires some affirmative opt-in beyond merely turning the device on, according to the Court. Sending an email through Gmail, storing a photograph in Google Photos, and managing a calendar entry each involves sharing information with a third-party company. “The point of carrying smartphones is to use what is on them,” the Court stated, quoting Carpenter’s recognition that apps and “services they provide” have become a “pervasive and insistent part of daily life.” A cellphone user should not be treated as having surrendered private information to the government “just by doing the ordinary things cell-phone users do,” the Court concluded.

Warrant Validity Left
to the Fourth Circuit

Having ruled that a search occurred, the Court turned to whether the geofence warrant rendered the search reasonable. The Fourth Amendment generally requires a warrant from “a neutral and detached magistrate,” who may issue it only when probable cause is properly established and the scope of the authorized search is described “with particularity.” Johnson v. United States, 333 U.S. 10 (1948); Kentucky v. King, 563 U.S. 452 (2011). The particularity requirement ensures that a search is “carefully tailored to its justifications” and does not take on “the character of the wide-ranging exploratory searches the Framers intended to prohibit.” Maryland v. Garrison, 480 U.S. 79 (1987).

The Court stated that the warrant in the present case was an uncommon, multi-step warrant in which Step 1 produced anonymized data for phones within the geofence; Step 2 authorized additional data, both inside and outside the geofence, for a subset selected by officers; and Step 3 authorized identifying information for a further subset, again selected by officers. The Court noted that the warrant said very little about how officers would make those choices at Steps 2 and 3. Because the Fourth Circuit had not addressed whether the warrant validly authorized each stage of the search process, the Court declined to resolve those questions in the first instance. Describing itself as “a court of review, not of first view,” the Court remanded for the Fourth Circuit to determine “whether, at each step of the search process, the warrant satisfied the Fourth Amendment’s requirements of particularity and probable cause.” Cutter v. Wilkinson, 544 U.S. 709 (2005). The Court also did not decide whether the good-faith exception to the exclusionary rule still permits admission of the Location History evidence under United States v. Leon, 468 U.S. 897 (1984). That question remains for the Fourth Circuit to consider on remand.

Conclusion

Thus, the Court held that police officers invade a cellphone user’s reasonable expectation of privacy when they access his Location History, regardless of the duration of data sought or its storage by a third-party technology company.

Accordingly, the Court vacated the judgment of the Fourth Circuit and remanded for further proceedings. See: Chatrie v. United States, 2026 U.S. LEXIS 2878 (2026).

Writer’s Note: Chatrie resolves the threshold search question but leaves the harder litigation questions open. On remand, the Fourth Circuit must decide whether the warrant satisfied probable cause and particularity at each step of the Google process. The Step 1 question is whether a warrant that begins with every responsive device inside a defined area and time is sufficiently particularized or instead resembles a general search that develops individualized suspicion only after the data is returned. At Steps 2 and 3, Justice Jackson’s concurrence, joined by Justice Sotomayor, identifies the central defect, viz., officers could obtain expanded location data and identifying information without returning to a magistrate for renewed probable-cause findings or judicially imposed narrowing criteria.

The good-faith issue also remains unresolved. The majority expressly declined to decide whether Leon still permits admission of the Location History evidence, leaving the Fourth Circuit to consider that question in light of the Supreme Court’s new substantive holding. For older warrants, the recurring remedial issue will be whether Chatrie sufficiently undermines the “novelty” rationale that has sustained good-faith reliance in prior federal geofence cases.

Chatrie also does not decide tower dumps, commercially purchased advertising-ecosystem location data, reverse-keyword warrants, AI-chatbot prompt searches, or other reverse-search techniques. The practical framework going forward should be functional rather than vendor-specific. Courts and counsel should ask whether the Government is using location or digital-query data to identify unknown people by searching first and developing suspicion later, whether the data is compelled or purchased, and whether a magistrate actually controlled the search before privacy was invaded.

Anyone interested in geofence warrants and the broader topic of reverse warrants is strongly encouraged to read the full opinions in Chatrie.  

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