Large format and highly detailed map of the state of New York, colored by counties. Shows, townships, towns, roads, railroads, rivers, mountains, canals and a host of other details. Large insets of the Hudson River from NYC to Saratoga Springs, the Vicinity of New York and Niagara River and Vicinity. A nice example.
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.