Dripps map of Frankford and vicinity, 1849
Pennypack Park Map
Plans and maps of the Pennypack Creek Watershed in Philadelphia
Map Lovers’ Monday: 1891 Water Supply Plan
Map of Frankford Borough, 1845
Philadelphia Navy Yard, July 1872
Darby, Delaware County, Pennsylvania, 1877
Drawing Dock Creek
Petition of manufacturers along the Schuylkill River in Philadelphia for a new upstream water supply, 1868
State of the Schuylkill River in 1876: Sewage pollution and possible remedies