How do I use maps offline on my iPhone?
Many times you will want to look at maps, but you're out in the middle of nowhere and don't have service. Although this feature isn't available for Apple Maps yet, you can save maps on Google Maps and look at them offline. To do this, look up your map in Google Maps, then type "ok map" in the search bar and hit search. This will give you an option to save the map to your places.
The map will expire after 30 days.