See Phillips page 680. Longitude from Philadelphia. This map is from the 1812 edition of Brooke's General Gazeteer Improved by Henry Brooke. The map shows the mid-Atlantic region from New Jersey west to Illinois and south to Kentucky. The northern boundaries of Indiana and Illinois run below Lake Michigan in this map and were later moved north.
Longitude is west from Philadelphia.
This map emphasises the coast and Pennsylvania is mostly a blank. It shows roads and the distances between towns and was engraved by Henry Tanner. Image from the Heritage Map Museum CD by permission. The map can be dated 1804-10 by the counties shown. Both east and west images are shown here.