Carpark is a clean and simple app for keeping track of where you parked your car.

After parking, open up the app and hit "Park" to drop a pin at your current location (or, if your device supports 3D Touch, use the home screen Quick Action to save yourself a tap.) Later, you can refer to the pin for location, time and estimated walking distance. No need to go back and delete old pins. Next time you hit "Park," the pin simply updates to the new location and you're free to go about your business.