Digital Elevation Models (DEM) are digitized versions of USGS's 7.5 degree topographic maps. With the help of additional software, they may be used to automatically define the base elevations for objects included in air dispersion modeling analyses. These DEM files can be downloaded from this website below. All DEM files on this site are listed based on the letter they begin with and are named based on the USGS quadrangle they represent.

Choose the letter with which the name of the quadrangle begins:

Choose the DEM file you wish to download:

Oakland
Oakland Acres
Oakville
Ocheyedan
Odebolt E
Odebolt W
Oelwein
Oelwein SE
Ogden
Okoboji
Olaf
Ollie
Olmitz
Omaha, MO
Omaha N
Omaha S
Onawa
Onawa SW
Oquaka
Orange City
Orchard
Orient
Osage
Osage SW
Osceola
Oskaloosa
Ostrander
Otley
Oto
Ottumwa N
Ottumwa S
Owasa
Oxford
Oxford Junction
Oyens