Lauren Feiner:

Facebook said that even when location tracking is turned off, it can deduce users’ general locations from context clues like locations they tag in photos as well as their devices’ IP addresses. While this data is not as precise as Facebook would collect with location tracking enabled, the company said it uses the information for several purposes, including alerting users when their accounts have been accessed in an unusual place and clamping down on the spread of false information.

Facebook acknowledged it also targets ads based on the limited location information it receives when users turn off or limit tracking. Facebook doesn’t allow users to turn off location-based ads, although it does allow users to block Facebook from collecting their precise location, the company wrote.

“By necessity, virtually all ads on Facebook are targeted based on location, though most commonly ads are targeted to people with a particular city or some larger region,” the company wrote. “Otherwise, people in Washington, D.C. would receive ads for services or events in London, and vice versa.”