Topographic (sometimes shortened to "topo") maps depict the rising and falling of the land with contour lines. The US Geological Survey (USGS) publishes topos for every state and territory. These maps also show cultural features (roads, buildings, developed areas) and physical features (rivers, streams, and lakes). Some of them maps also show vegetation. The largest scale US topographic maps are produced at a scale of 1:24,000 and cover an area 7.5' x 7.5' (one-eighth of a degree square). The USGS also produces intermediate-scale topographic at scales of 1:100,000 and 1:250,000 that cover 30' x 60' (one half of a degree by a degree) and 1° x 2° (one by two degrees), respectively. For more information on USGS topographic maps and topographic map symbols, consult the following USGS' web sites:
The IUB Library collects topographic maps from around the world, with special emphasis on maps covering the state of Indiana. You might find them in GIMMS, the ALF, or the Lily library, but all cataloged maps will note where they can be found in IUCat.
GIMMS receives current USGS maps through the Depository program and retains them over time, but most of these maps are in the ALF. For immediate access to USGS Topographic maps, see the National Map.