A topographic map shows physical and human features of the area shown. A topographic map may show roads, contour lines for elevation, rivers, schools, post offices, individual mountain peaks, national and state parks and forests and towns.
Almost every country has some kind of mapping agency responsible for creating topographic maps. For the United States, it is the Geological Survey. For Canada, it is Geomatics Canada within Natural Resources Canada, in Mexico, it is the Instituto Nacional de Estadistica Geografia e Informatica (INEGI) and in Great Britain, it is the Ordnance Survey.
Curious about other national mapping agencies around the world? See the book below.
The U.S. Geological Survey is the largest supplier of topographic maps for the United States. You can buy maps directly from them or download topographic sheets. The USGS has a new digital format for its maps. It is called a GeoPDF. You can use Adobe Acrobat Reader to view these new maps. You can even download an add-on that is specific to GeoPDF's. The add-on gives you tools that allow you to measure distances, make notations and view in Google Maps.