In a memo sent to Sen. Ron Wyden (D-OR) and obtained by The New York Times, the Defense Intelligence Agency (DIA) admitted that it buys location data from brokers — and that the data isn’t separated by whether a person lives in the US or outside of it.
Data brokers are companies that, as the name implies, collect and sell people’s information. The companies collect people’s location information (and much more) by paying app makers and websites for it.
Once the broker has the information, they can aggregate it and sell it to whoever’s willing to pay for it — including the US government.