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

The Hidden Cost of Location Data

If you use a mobile phone with location services turned on, it is likely that data about where you live and work, where you shop for groceries, where you go to church, and where you traveled over the holidays is up for sale. This information can be accessed by various entities, including government agencies like U.S. Immigration and Customs Enforcement (ICE).

The U.S. government doesn’t need to collect this data itself because your mobile phone is already doing it. While location data is sometimes collected as part of an app’s intended use, such as for navigation or weather forecasts, more often it is collected invisibly in the background. As a privacy researcher who studies how people understand and make decisions about their data, I have found that once you give an app or website permission to collect location data, you lose control over how it is used and shared.

Why Mobile Phones Collect Location Data

Mobile phones collect location data for two main reasons: as a by-product of their normal operation and because they are required to do so by law.

Phones constantly scan for nearby cell towers to ensure that when someone wants to place a call or send a text, the phone is already connected to the closest tower. This makes calls and texts faster. To maintain quality of service, phones often connect with multiple cell towers at once. The range of a cell tower's signal can be thought of as a large bubble, and the phone's location can be calculated through triangulation based on the intersection of these bubbles.

In addition to cell tower triangulation, since 2001, mobile phone carriers have been required by law to provide latitude and longitude information for phones used to call 911. This helps emergency responders reach people faster.

How Location Data Ends Up Being Shared

When users allow websites and apps to access their location data, the software developers can share that data widely without asking for further permission. Sometimes, apps directly share data with data brokers through partnerships. More commonly, apps and websites that include advertisements share location data via a process called "real-time bidding." This involves third parties hired by advertisers who place automated bids on ad space to target specific audiences.

To identify the right audience, software embedded in the app or website shares user information, including location, with these third parties. These middlemen can keep the data and use it however they want, 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 acquired, the data from location data brokers is sold widely. Companies known as location-based service providers repackage it and sell access to tools that monitor people’s locations. Some of these tools provide roadside assistance, while others are 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 type of data is extremely sensitive and cannot be made anonymous. The two most common locations a person visits are their home and workplace. From this information alone, it is easy to determine a person’s identity and match it with other data that companies have acquired.

Most people don’t realize that the location data they allowed apps and services to collect for one purpose, like navigation or weather, can reveal sensitive personal information that they may not want to be sold to a data broker. For example, a research study I published about fitness tracker data found that even though people use location data to track their exercise routes, they didn’t think about how that 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 the normal use of their mobile phones might be available to entities like ICE.

More restrictions on how mobile phone carriers and apps are allowed to collect and share location data—and on how the government is allowed to obtain and use location information—could help protect your privacy. So far, efforts by the Federal Trade Commission to curb carriers’ data sales have had mixed results in federal court, and only a few states are attempting to pass legislation to tackle the problem.