This item is a land survey map of southern Chester County, Pennsylvania, and northern Delaware, showing individual family properties. The identities of the maps's surveyors, John Harlan and Sam Sharp, are unknown. Despite not being able to positively identify either surveyor, genealogical evidence supports the premise that the surveyors of the map were likely related, at least by marriage.

Northern Delaware (current day New Castle County) was settled by Swedes in the seventeenth century. This collections contains ten aerial photographs of the Northeastern Delaware border with Pennsylvania, along the Delaware River.