Note: NED data can be accessed through The National Map (USGS). Instructions are available on The National Map Viewer homepage. The National Elevation Dataset (NED) is the primary elevation data product produced and distributed by the USGS. The NED provides the best available public domain raster elevation data of the conterminous United States, Alaska, Hawaii, and territorial islands in a seamless format. The NED is derived from diverse source data, processed to a common coordinate system and unit of vertical measure. All NED data are distributed in geographic coordinates in units of decimal degrees, and in conformance with the North American Datum of 1983 (NAD 83). All elevation values are provided in units of meters, and are referenced [...]
The National Elevation Dataset (NED) is the primary elevation data product produced and distributed by the USGS. The NED provides the best available public domain raster elevation data of the conterminous United States, Alaska, Hawaii, and territorial islands in a seamless format. The NED is derived from diverse source data, processed to a common coordinate system and unit of vertical measure. All NED data are distributed in geographic coordinates in units of decimal degrees, and in conformance with the North American Datum of 1983 (NAD 83). All elevation values are provided in units of meters, and are referenced to the North American Vertical Datum of 1988 (NAVD 88) over the conterminous United States. The vertical reference will vary in other areas. NED data are available nationally at resolutions of 1 arc-second (approx. 30 meters) and 1/3 arc-second (approx. 10 meters), and in limited areas at 1/9 arc-second (approx. 3 meters). At present, the bulk of Alaska is only available at a 2 arc-second (approx. 60 meters) resolution, owing to a lack of higher resolution source data, though some areas are available at resolutions of 1 and 1/3 arc-second with plans for significant upgrades of the state over the next five years. The NED is updated on a nominal two month cycle to integrate newly available, improved elevation source data.
