1×2-Degree Quadrangle Geologic Maps
These maps cover 1 degree of latitude by 2 degrees of longitude and are the standard series for intermediate-scale geologic mapping. In this series, one inch on the map represents 250,000 inches, or about 4 miles, on the ground.
To obtain maps: Click on map area to view popup windows containing map information and links to purchase printed and/or digital copies, or to download a pdf map or a zip file with GIS data (if available).
Maps at other scales cover some of the gaps in 1×2-degree map coverage: 30’x60′ quadrangle geologic maps, 7.5′ quadrangle geologic maps. Other geologic maps include non-quadrangle geologic maps and national & state parks geologic maps.