These topo maps come on three CDs to cover the whole US.  They are: USA West (Setup), USA East, and Alaska/Hawaii.  Areas to be selected are now rectangles of various sizes in a grid.  The topographic data has been taken from the USGS 1:100,000 topo maps and can be uploaded to all Garmin mapping units.  Due to the density of the data, less area can be uploaded to a unit than the street-level maps.  Increasing your map memory will help.

Contour lines are at 10 to 50 meter intervals depending to the steepness of the terrain.  For example, in mountainous areas of Oregon the contour lines are 40m intervals -in Atlanta, 10m.  On the larger lakes, elevation contours (not depth contours) are also shown. (Samples shown below).

The map data contains highways, roads, hiking trails, snowmobile trails, backwoods trails, elevation contours, point elevations, summits, some bathymetric contours, geographic names, churches, and schools.  Shoreline detail is included for lakes, reservoirs, small bodies of water, waterways, rivers, and streams.  Icons represent boat ramps, dams, marinas, campgrounds, public facilities, mile markers, first-aid stations, picnic, swimming, and ski areas, wrecks, fuel, and dangerous and restricted areas.

In addition, nautical navaids for the 50 states are provided, including radio beacons, RACONs, fog signals, river, harbor, and other lights, day beacons, and lighted and unlighted buoys. Wrecks and obstructions such as shipwrecks, submerged rocks, obstructions and other hazards to nautical navigation are displayed.

Gamin has advised us that the database is older than any of their current maps, so expect the road data to be about 30 years old.  (However, the contours haven't changed much!)  The small stream data is about as extensive as possible with some streams traced back to the spring they come from.

It appears that the Garmin topo maps have more detail than the Magellan MapSend Topo USA maps, but about the same as Magellan's Topo 3D USA maps.  For a comparison of the Garmin and Magellan topo maps, see (HERE).

For the origin of Garmin's USA Topo Data, see (HERE).  A comparison of the Garmin maps to other map products are shown (HERE).