Yes, the Government Can Track Your Location – But Not Always by Spying on You

Understanding How Mobile Phones Collect Location Data

Mobile phones are more than just communication devices; they are constantly collecting data about your movements. If you use a mobile phone with location services enabled, it is likely that information about where you live, work, shop, and even travel is being gathered. This data can be sold to various entities, including government agencies like U.S. Immigration and Customs Enforcement (ICE). The U.S. government doesn’t need to collect this information directly because your mobile phone is already doing it for you.

Location data is often collected as part of a mobile phone app's intended use, such as for navigation or weather forecasts. However, more frequently, this data is collected in the background without your explicit knowledge. As a privacy researcher, I study how people understand and make decisions about data collected about them. I also explore ways to help consumers regain control over their privacy. Unfortunately, once you give an app or website permission to access your location data, you lose control over how that data is used and shared.

Why Mobile Phones Collect Location Data

There are two primary reasons why mobile phones collect location data: as a by-product of their normal operation and because they are required to do so by law. Mobile phones continuously scan for nearby cell towers to ensure quick connectivity when making calls or sending texts. This process involves connecting to multiple cell towers simultaneously, which allows for triangulation to determine a phone’s location based on the intersection of the signal bubbles from each tower.

Additionally, since 2001, mobile phone carriers have been legally required to provide latitude and longitude information for phones used to call 911. This helps emergency responders reach individuals faster. The "Today" show has highlighted how your phone reveals where you go and what you do through these mechanisms.

How Location Data Ends Up Being Shared

When users allow websites and apps to access their location data, the software developers can share this information widely without seeking further permission. Sometimes, apps directly share data through partnerships with data brokers. More commonly, apps and websites containing advertisements share location data via a process known as "real-time bidding." This process determines which ads are shown and involves third parties hired by advertisers who place automated bids on ad space.

These third parties receive user information, including location data, to identify target audiences for ads. They act as middlemen who can retain the data and use it however they see fit, including selling it to location data brokers, regardless of whether their bid wins the auction for the ad space.

What Happens to the Data Once It Is Shared

Once location data is acquired by data brokers, it is sold widely. Some companies repackage this data and sell access to tools that monitor people’s locations. These tools can serve various purposes, such as providing roadside assistance, but they can also be used by police, government agencies, and others to track individuals.

In October 2025, news outlets reported that ICE purchased a location surveillance tool from a company called Penlink. This tool can track the movements of specific mobile devices over time in a given location. Such tools allow users to access location data from "hundreds of millions of mobile phones" without a warrant.

Why It Matters

The invisible collection, sale, and repackaging of location data is a significant issue because this information is extremely sensitive and cannot be made anonymous. The two most common locations a person visits—home and work—can easily reveal their identity and match it with other data these companies have collected.

Most people are unaware that the location data they allow apps and services to collect for one purpose, such as navigation or weather, can reveal sensitive personal information that they may not want to be sold to data brokers. For example, a research study I published on fitness tracker data found that even though people use location data to track their exercise routes, they don’t consider how this data could be used to infer their home address.

This lack of awareness means that people can’t be expected to anticipate that data collected through normal phone use might be accessible to entities like ICE. Implementing more restrictions on how mobile carriers and apps collect and share location data, as well as how the government obtains and uses this information, could help protect privacy. So far, efforts by the Federal Trade Commission to curb data sales have had mixed results in federal court, and only a few states are attempting to pass legislation to address the issue.