Detailed map, colored by counties and showing Indian Reservations, mountains w/elevations, lakes, some townships, roads, railroads, stations, towns, etc. One of the best regional maps of Colorado to appear in an atlas and one of the earliest to show Colorado as a single state.
O. W. Gray was a publishing firm based in Philadelphia. Later, they published as O. W. Gray & Son. They published atlases in the late nineteenth century. Gray's National Atlas was one of the most successful commercial ventures of the 1870s and one of the last to employ hand coloring on maps.