A map is a representation of the earth, or part of it. The distinctive characteristic of a topographic map is the use of contour lines to show the shape of the earth's surface. USGS topographic maps also show many other kinds of geographic features, including roads, railroads, rivers, streams, lakes, buildings, built-up areas, boundaries, place or feature names, mountains, elevations, survey control points, vegetation types, and much more.
A contour line joins points of equal height. Contours make it possible to show the height and shape of mountains, depths of the ocean bottom, and steepness of slopes. Basically, contours are imaginary lines that join points of equal elevation on the surface of the land above or below a reference surface, usually mean sea level.
The phrase "USGS topographic map" usually refers to standard quadrangle maps with scale between 1:10,000 and 1:250,000. Within this domain there are two product categories:
maps are the current topographic map series, published as digital documents in 2009 and later.
The USGS also publishes other kinds of maps, including some topographic maps that are not standard quadrangle maps. For information about other maps and publications, see
How do I download USGS topographic maps?
I want to buy a topographic map. How do I get it?
What map series and scales are included in the HTMC?