BackCountry Navigator PRO GPS

Use your phone or tablet as an offroad topo mapping GPS with the bestselling outdoor navigation app for Android! Explore beyond cell coverage for hiking, and trekking.

Download topo maps for the US and some other countries in advance, so you won't need cell coverage when navigating.

This uses many publicly available map sources as free downloads. It also has some additional content available as an in app purchase:
-Accuterra Topo Map Source on sale for a $22 upgrade. This can be purchased and used with or in instead of the free sources.
- Boundary maps for 12 western states from the Bureau of Land Management(BLM) for $7.99. Overlay for topo maps hunters.
-Content from US TrailMaps for $15.99, including:
-Snowmobile Trail Maps for Snowmobiling enthusiasts,
-ATV Trail Maps
-Whitewater Trail Maps,
-Equestrian Trail maps.
See these in the menu under More-> "Purchasing AddOns". They can be shown on top of topo maps.

You may try the DEMO version to make sure you like the maps in your country.

Use offline topo maps and GPS on hiking trails without cell service! The GPS in your Android phone can get its position from GPS satellites, and you don’t have to rely on your data plan to get maps. Have more fun and safe GPS adventures in the backcountry.
  
Add custom GPS waypoints in longitude and latitude, UTM or MGRS grid reference. Import GPS waypoints from GPX files. Choose mapsource-like icons for GPS waypoints. (This app uses the WGS84 datum, NAD27 is available in settings).  

Use GPS for hunting a waypoint or geocache, for recording tracks and GPS waypoints on your trip, all the while tracking your GPS quest on topographic maps.

About topo (topographic) maps: Topo maps show terrain through color and contours, and are useful for navigation offroad. Topo maps and GPS can be used for hiking, hunting, kayaking, snowshoeing, & backpacker trails.
You can create your own maps with Mobile Atlas Creator. Built in sources include:
OpenStreetMaps and NASA landsat data worldwide
OpenCycleMaps showing terrain worldwide
USA Topo Maps
USTopo: Aerial Photography with markup.
NR Canada Topo Maps from Toporama
NOAA RNC Nautical Charts (coastal)
USGS Color Aerial photography    
Topographic Maps of Spain and Italy
Topo maps of New Zealand
Above sources are generally free to use.

Here are some of the outdoor GPS activities BackCountry Navigator has been used for:
As a hiking GPS both on hiking trails and off trail.  
Camping trips to find that perfect camping site or find your way back to camp with GPS.
Hunting trips for hunting wild game in rugged areas.
Doing recon for a hunt or a live hunting trip.    
Fishing: mark your favorite fishing spots and navigate with GPS.
Search and Rescue (SAR).
Trekking the Pacific Crest trail or other long term hiking.
Kayak and canoe trips on inland lakes and streams or marine, coastal waters.  
Backpacker trips: using topo maps of wilderness areas and national forests to navigate on trails with the GPS. Have this in your rucksack or backpack.  
Snow adventures including snowmobiling, skiing (alpine or cross country) and snowshoeing. Try this with snowmobile trails addon.

Find your own ways to have fun in the outdoors. Be a maverick by venturing into new territory beyond cell service boundaries with your GPS. Become a pro at navigation with GPS for allsports for the outdoors.

BackCountry Navigator has been previously available on WM devices and preloaded on the Trimble Nomad outdoor rugged device. This Android version is more flexible, featured, and fun.

For a one time fee, this a great addition to the outdoor gear you bought at Cabelas, REI, or another outdoor store. Many have found the Android GPS in a phone or tablet to substitute for a Garmin GPS, such as the Garmin Montana GPS, Garmin Etrex GPS, or the Garmin Oregon GPS. This is also a cheaper alternative to the Magellan Explorist series handheld GPS.