USGS
Mission: The USGS serves the Nation by providing reliable scientific information to describe and understand the Earth; minimize loss of life and property from natural disasters; manage water, biological, energy, and mineral resources; and enhance and protect our quality of life. Vision: USGS has become a world leader in the natural sciences thanks to our scientific excellence and responsiveness to society's needs. Summary provided by http://gisdata.usgs.net/
DOI/USGS/EROS/GISDATA