Where are you right now? Where were you an hour ago, or yesterday at noon? Do you consider that information private? The U.S. Supreme Court generally agrees that you should.

That may be oversimplifying it, but a landmark decision handed down on June 29, 2026, makes clear that your location history carries a reasonable expectation of privacy under the Fourth Amendment.

In my March 2026 column (www.securityinfowatch.com/55359265), I wrote about Chatrie v. United States, which was then pending before the Supreme Court. The case concerned police access to geofence data – digital records of a person's location maintained in a smartphone or cloud computer. The central question: does law enforcement's gathering of that location data constitute a "search" under the Fourth Amendment, thereby triggering its constitutional protections? On June 29, the Court answered yes, by a 6–3 vote.

Here's what happened. Chatrie robbed a federal credit union at gunpoint and made off with nearly $200,000. Law enforcement served Google with a geofence warrant directing the company to produce location data for cellphone users in the vicinity of the bank during the robbery. Google first returned a list of 19 anonymous accounts linked to devices within 150 meters of the bank during the 30 minutes before and after the robbery. The government then narrowed its request to nine of those accounts, then to three – one of which belonged to Chatrie. Relying on that location data, law enforcement obtained a warrant to search two residences linked to him, where they found nearly $100,000 in stolen cash, a gun, and demand notes.

Good police work – or a violation of Chatrie's rights? That question ran through every level of the federal courts. The trial judge denied Chatrie's motion to suppress the geofence evidence. The Fourth Circuit upheld that ruling. The Supreme Court reversed.

In the majority opinion, the Court reaffirmed that the Fourth Amendment's purpose is to safeguard the privacy and security of individuals against arbitrary invasions by governmental officials. Historically, that meant assessing whether there was an unreasonable physical intrusion on private property. More recently, the inquiry has shifted to whether a search invades an area a person seeks to preserve as private – and whether that expectation is one society is prepared to recognize as reasonable.

The Court found that even a brief window of location data can implicate serious privacy concerns. As the majority noted, a short period of location history can reveal visits to a psychiatrist, a plastic surgeon, an abortion clinic, a criminal defense attorney, or a by-the-hour motel. The examples are vivid, and the point lands.

Critically, the Court did not categorically ban geofence warrants. Instead, the justices remanded the case to the Fourth Circuit to determine whether the specific, multi-step warrant used in the Chatrie investigation satisfied the Constitution's requirements of probable cause and particularity. Whether the warrant – and therefore the conviction – survives that scrutiny remains to be seen.

The practical implications are significant. Those seeking large volumes of location data are now subject to stricter constitutional review, making it harder for law enforcement to sweep up information about everyone near a crime scene. Technology companies are adjusting as well. Google now stores location history on the device rather than in the cloud, making that data far harder to access without physical possession of the phone or knowledge of its owner. Both developments will complicate future criminal investigations.

Chatrie belongs in prison – and is in prison for now. But the law sometimes errs in favor of the broader good. A prosecution built on a violation of a defendant's rights must be weighed against the risk to society posed by unchecked government access. I hope the conviction survives on remand, but that question was not resolved by this decision.

What was resolved is this: location data is now constitutionally protected in a way it was not before. The Court's reasoning was grounded not in an abstract constitutional principle but in the practical reality of how much a few hours of location data can reveal about a person's private life. That reasoning will carry into future cases involving other kinds of digital data, and it should inform how the security industry thinks about the data it collects.

For professionals who deploy, integrate, and manage systems that generate exactly this kind of data, the shift matters in concrete ways. Cameras, access control systems, mobile credentials, and cloud-connected platforms all leave location trails.

Clients and end-users rarely think about this. They see hardware on a wall or an app on a phone; the data those systems generate is invisible to them but legally significant. Understanding where the constitutional lines are being drawn is no longer optional. It is part of operating responsibly in an industry that is, increasingly, in the data business whether it intends to be or not.