In 1739, America's first botanist, John Bartram of Philadelphia, followed the course of the Delaware River in his search for American trees, evergreens and shrubs to supply new species that were formerly unknown to British naturalists. These gardeners waited months for shipments of saplings, seeds, and pinecones to be sent by sea that were then introduced into English gardens. Using Native American trails , Bartram rode on horseback through the Water Gap, which allowed entry to the lands beyond.
Steep rock walls prohibited foot travel through the gap until a road was built on the Pennsylvania side of the river in 1793. In 1830 a road was built on the New Jersey side through the gap and north toward Pahaquarry. Interstate 80 passes through the gap on the New Jersey side as of the early 1970s via the Delaware Water Gap Toll Bridge. The Pennsylvania portion of the New Jersey Cut-Off mainline of the Delaware, Lackawanna and Western Railroad comes into Slateford, PA. The Pennsylvania Northeast Regional Rail Authority owns the trackage in the Water Gap area and is operated by the Delaware-Lackawanna Railroad. Pennsylvania Route 611, which is adjacent to the railroad for most of way through the gap, occupies the right-of-way of a former trolley line. Interstate 80 occupies the former right-of-way of the New York, Susquehanna and Western Railway.
In 1962, Congress authorized the building of a dam across the Delaware River at Tocks Island, upstream of the water gap. Meant to control hurricane-related flooding, it was never built. The land for the proposed reservoir, which had already been purchased, was used to create the Delaware Water Gap National Recreation Area in 1965.