The most accurate and up to date maps available for public purchase are made by the United States Geological Survey. Printed maps may be ordered or free topographical and historical maps can be downloaded from the Maps, Imagery and Publications link on the USGS website.
The USGS is the country's largest civilian water, earth and biological science mapping agency. It was established on March 3, 1879, and has continued to collect information to produce reliable maps of the United States. Thousands of scientists, technicians and support staff work from over 400 USGS locations every day to record and document geological phenomena for mapping and environmental studies.