Manually Clear Cache in Google Maps for IPhone and Free up Space
Offline mode in Google Maps is great , but when you add data, the app automatically caches cookies too, which can take up a lot of space. Luckily, OS X Daily reminds us that there is a way to clear this cache, it’s just hidden in a very strange place.
When you do, you will delete everything on Google Maps, including cache data, cookies, and your offline maps. Depending on how many cards you have saved, this can free up a ton of space at the same time. Open Google Maps, tap the menu icon in the upper-left corner of the search bar, then tap Settings> About, terms & privacy, then tap Clear app data. This completely resets Google Maps and clears everything up so you can start from scratch. If you just need to remove multiple offline maps, you can do so in Settings> Offline Areas.
Clear Google Maps Cache Manually on iPhone | OS X Daily