I personnaly use OSMAnd, but the UI can be... demanding. Another app that has been praised by a lot of people is CityMaps2go [0], both on Android and iOs. Whil

I personnaly use OSMAnd, but the UI can be... demanding. Another app that has been praised by a lot of people is CityMaps2go [0], both on Android and iOs. While the application is not open-source (which is why I don't use it), the underlying data comes from OSM, so by using this application you're fighting for OSM. [0] https://play.google.com/store/apps/details?id=com.ulmon.android.citymaps2go https://play.google.com/store/apps/details?id=com.ulmon.andr...