There are a few different ones for iOS and Android.

Try "maps.me" which is available for both and free. This does offline routing.

Osmand is also available for both but it's new (not complete) for iOS (which means it's better for Android at the moment). Try the free version but buy it to use (it's cheap). The interface isn't the greatest. This does offline routing too.

Galileo is good for iOS (it's new/incomplete on Android at the moment). Again, try the free version but use the paid version. Galileo doesn't do routing.

Locus Pro (on Android) has a lot of features but you have to figure out how to download free maps to it (otherwise, you have to buy maps through the Locus store).

All of these I've mentioned are actively being improved.


Most of the mapping apps use data from Openstreetmap (OSM). That data is generally pretty good but it isn't perfect (and might be better in some places than others).