The United States Geological Survey (USGS) is the federal agency responsible for surveying and publishing maps of topography (giving landscape relief and elevation), geology, and natural resources—including minerals, fuels, and water. The USGS, part of the U. S. Department of the Interior, was formed in 1879 as the United States began systematically to explore its newly expanded western territories. Today it has an annual budget of about $700 million, which is devoted to primary research, resource assessment and monitoring, map production, and providing information to the public and to other government agencies.

The United States Geological Survey, now based in Reston, Virginia, originated in a series of survey expeditions sent to explore and map western territories and rivers after the Civil War. Four principal surveys were authorized between 1867 and 1872: Clarence King's exploration of the fortieth parallel, Ferdinand Hayden's survey of the Rocky Mountain territories, John Wesley Powell's...