How to Use Offline Maps with No Signal on iPhone (USGS Download, MBTiles, Custom Tiles)

TL;DR

Before you go, frame an area on the Map, pick a USGS source and detail level, and download it into an MBTiles file (up to 50,000 tiles). Outside the US, import a raster .mbtiles or add your own tile URL. GPS, grid and navigation need no signal; Apple Maps tiles do.

The problem

The trail head has no signal. Phone maps turn into a grey grid exactly where you need them. Turn-by-turn road apps don’t understand “off the track”, and a paper map can’t tell you your grid.

What works with no signal

  • Your position and MGRS grid (GPS only)
  • Waypoints, routes, tracks and drawing
  • Bearing, distance, cross-track, magnetic declination (offline WMM2025)
  • The map grid overlay
  • Any downloaded or imported base map

What does not work offline: Apple’s Standard/Satellite/Hybrid map tiles, and place-name search (typed grids and coordinates still work).

Download an area (US)

  1. While you still have a connection, open Map and tap the download button.
  2. Pick a Source: USGS Topo, USGS Imagery Topo or USGS Shaded Relief.
  3. Drag the box over the area and resize it with the corner handles.
  4. Choose the Detail level (zoom range up to z16). The panel shows the tile count and size before you start.
  5. Tap Download. Progress shows on the map; it’s resumable.
  6. Choose the downloaded layer as your map source. It’s listed under Offline Maps in Settings.

If it says the area needs too many tiles (limit 50,000), shrink the box or lower the detail.

Manage storage

Settings → Map → Offline maps lists installed maps with their size on disk. You can rename, delete, or delete all. Deleting frees the space and can’t be undone.

Import your own (anywhere in the world)

  1. Get a raster .mbtiles file, from a map provider or one you made yourself.
  2. In Offline Maps choose Import MBTiles… and pick the file.
  3. Select Offline tiles as the map source.

Add a tile server

If you have your own server (or a licensed one), enter its URL with {z}, {x} and {y} placeholders under the custom tile settings, write it exactly as the service documents (ArcGIS often uses {z}/{y}/{x}), then choose Custom tiles as the source. You can download it for offline use.

Before you go

  1. Download the area and the surroundings, with one zoom level of margin.
  2. Switch to airplane mode and check the map still draws.
  3. Mark your start point as a waypoint.

FAQ

Does the standard Apple map work offline? No. The Standard, Satellite and Hybrid layers load from Apple and need a connection. Download a USGS area, or import MBTiles, for offline.

Where does the USGS data cover? The United States. Elsewhere import a raster .mbtiles file or add your own {z}/{x}/{y} tile server.

How big can a download be? Up to 50,000 tiles per area. The panel shows the tile count and size before it starts; if it’s too large, reduce the box or the detail.

Do the GPS and grid need data? No. Position, MGRS grid, waypoints and bearing navigation all work with no signal.

Whose licence applies to custom tiles? Yours. The app warns that you are responsible for the licence and usage policy of any server you add, including whether it allows downloading.

The app MGRS GPS →