This is an outstanding and quite rare folding pocket map of the United States with still evolving states.  With the separation of West Virginia a few years prior to issue, evolution is still occurring in the West: Arizona territory includes the southern tip of today’s  Nevada; Utah to the west is still oversized; and, a large Dakota territory includes its namesakes, and today’s Wyoming and parts of Nebraska and Idaho.  The map is expectedly well detailed with topographical elements, towns, cities, forts, and Indian tribes as well as several proposed routes for a transcontinental railroad, the Pony Express route, and the U.S. Mail Route.  Vignettes included are a sailing ship and the Capitol building, and in customary Colton fashion, is surrounded by a floral border.  Multiple fonts are used in state names, and some are crude (see OHIO), suggesting that this was either a short lived edition or a proof.  There have been only two previous known listings in past 30 years.