This tutorial will direct you to download DEM data for the US: http://www.gpsfiledepot.com/tutorials/how-to-create-garmin-topo-maps---part-2---elevation-data/

This tutorial will direct you to download DEM data for the US: http://www.gpsfiledepot.com/tutorials/how-to-create-garmin-topo-maps---part-2---elevation-data/ http://www.gpsfiledepot.com/tutorials/how-to-create-garmin-t... The map viewer you use: http://viewer.nationalmap.gov/viewer/ http://viewer.nationalmap.gov/viewer/ Info about the elevation data you get: http://nationalmap.gov/3DEP/3dep_prodserv.html http://nationalmap.gov/3DEP/3dep_prodserv.html The data is kind of buried, but I went through this process for building maps and it appears to be very high quality.