Whenever you are accessing Google maps, just enter “OK Maps.” The map that you are currently seeing in your screen will be saved on your device.
All you need is to pan and zoom in on the area that you want to save for offline use. Then type “OK Maps” (“without the quotes) in the search box and click on Search.
After it is saved, you can use that map even when there is no internet connection on your device. It even lets you zoom into the map for more details. This works on Google maps app for both Android and iOS devices.