The US Geological Surveys online Geographic Names Information System contains data on nearly 2 million physical and cultural geographic features in the US. Facts include federally recognized feature name, feature type, elevation, estimated 1994 population of incorporated cities and towns, state and county in which the feature is located, latitude and longitude of the feature location, and more. Searches can be done by feature name or type, state, county name, elevation range, and population range. A simple but useful site.