An excellent map of the region bounded by the Rockies in the west and the Sioux and Red River of the North on the east.
Colorado is showing the signs of its mining boom. Wyoming is limited to 4 counties, and is still largely unexplored in the north, as is Montana. Dakota has only one line of eastern Counties. Kansas and Nebraska still lack many western counties.
The map includes lots of Indian names and reservations, forts, rivers, mountains, railroads, explorers routes, etc.