I use Pocket Earth Pro on my iPhone but don't know if they have an Android version. It has good downloadable maps that can be tailored to regions within a country. In the US it's States of course, but elsewhere may be a different designation. Within a State you can download a single state, or just a city within a state. You can just as easily erase them to clean up your memory use if that might be an issue. I like that it shows footpaths and trails that have been accurate when I traveled them. Nice for parks and wilderness areas with designated hiking trails.