This data set was created as part of a project to improve and update the delineation of the State boundary between New Jersey and Pennsylvania. Exhaustive work was carried out using available aerial imagery from various time periods, several decades of USGS Topo maps, tax maps and other historical maps. This included portions of the original map surveyed for the 1786 bi-state commission report to determine which islands from the report still exist and could be identified. Several islands were found to no longer exist because accretion of deposited materials filled in the area between island and mainland or the island disappeared under the river’s surface through erosion. In addition, many of the islands are no longer known by the names listed in the 18th century report and had to be cross-referenced between maps of various vintages and other historical information.