United States, Pennsylvania, Philadelphia, Navy Yard, Philadelphia
39.927632 -75.147176 +-6208m. WGS84
The "Old Navy Yard" and Ballast Grounds below it, referred to on label, is N of the current Navy Yard, fide https://www.jstor.org/stable/pdf/4059588.pdf. Point has been placed at Front and Tasker Streets. Error radius extended S to League Island, Navy Yard (seen on Philadelphia 1891 USGS topo. map).