This research guide was created by Thelma Thompson, Government Information and Map Librarian (now retired), and is currently maintained by other librarians at UNH.
The UNH Library is no longer receiving USGS topographic maps on paper from the US government. We have kept the final print maps we've received (generally pre-2010) but they are no longer the most recently produced.
US Topo maps are updated and superseded every three years (except for Alaska).
For the most recent edition of each US Topo for download or purchase, go to
Topographic maps show three dimensional features of the earth landforms based on topographical surveys. Most topographic maps use contour lines to show elevation change including valleys, sea floors, and mountain ranges. Other topo maps show man-made features of an area such as roads, cities, railroads, pipelines, fence lines, bodies of water, trees, wells, buildings, and cemeteries.
Some of the most common topo maps were produced by the U.S. Geological Survey's (USGS) National Program for Topographic Mapping between 1884–2009. The majority of USGS published topographic maps are in the 1:24,000/1:25,000-scale map series; the exact scale of this map is 1:24,000 which means that one inch on the map equals 24,000 inches on the ground or 2000 feet.
This series is also known as the 7.5-minute map series because these maps generally each cover a single geographic quadrangle bounded by 7.5 minutes of latitude and 7.5 minutes of longitude. The original USGS 7.5-minute topographic map series (1945-1992) included feature classes that are not yet shown on current US Topo maps.
They form useful "base maps" for displaying a variety of other information.
When used with historic maps and air photos or older satellite imagery, they can help in documenting changes.
Other uses can include
