Question : Where can I find a Terrain Elevation Database of the United States?

I'm a pilot and developer and am currently writing an aviation safety application. I need to be able to search a point on earth (using coordinates for instance) and determine what the maximum elevation is for that square area. 1km resolution is more than fine as I'm looking to simply get the maximum terrain elevation along a course line.

I know there are county and zip code databases that have elevation, but that's not nearly enough resolution as there are some very remote areas that we fly in that are much higher than these databases can provide for.

Answer : Where can I find a Terrain Elevation Database of the United States?

http://freegis.org/database/?cat=1

Looks like either GLOBE or GTOPO30 contain what you are looking for.