You may not be aware, but by default your iPhone actually keeps track of places you’ve frequently visited and when you were there. While this is done primarily to aid in features like navigation in the iOS Maps app and for iOS 9’s “Proactive Assistant” to help figure out when you’re most likely going to work or the grocery store, you can also see the data for yourself. While the set of places isn’t comprehensive — it’s based on frequently visited locations, rather than a list of everywhere that you’ve been even once — it can still be handy if you’re trying to figure out when you were last out at a specific location.
You’ll need to dig deep into the iOS Settings app to find it — specifically going into Privacy, Location Services and then scrolling down all the way to the bottom to find System Services, where Frequent Locations will appear among other iOS features that use the location monitoring services.
In the Frequent Locations section, you’ll see a list of cities and other major geographical areas you’ve frequently visited, with the number of unique locations recorded and the range of dates that you visited those locations. From there you can see a list of specific locations within each area, with a list of the number of times you’ve visited, and can tap on an individual location to see a list of the specific dates and times that you were at each of those locations.
While Apple promises that this location data is stored only on the iPhone itself and never transmitted to Apple, if you’re uncomfortable with this tracking going on, it can be turned off and you can clear the existing stored history from the initial screen. However, keep in mind that by doing this you’ll lose access to personalized features like predictive traffic routing and automatic directions to regular destinations like work and home, which depend on your iPhone keeping track of this information.