Elevation data: 250k DEM's: (USGS DEM format): Digital elevation model and index map. What is a DEM? (USGS).
Elevation data: 100k DEM's: (USGS DEM format). About 2-Arc-Second DEM's (USGS).
Elevation data: 24k DEM's: About 7.5-minute DEM's. ArcView extension to convert USGS SDTS DEM format.
National and international elevation data
