The Delaware Water Gap is a geologic formation on the border of New Jersey and Pennsylvania, where the Delaware River traverses a large ridge of the Appalachian Mountains. The Worthington State Forest is to the immediate northeast on the New Jersey side of the border. U.S. Interstate 80 also passes through the gap.

The Delaware Water Gap, viewed from the air, looking north.

The Delaware Water Gap is the site of the Delaware Water Gap National Recreation Area , which is used primarily for recreational purposes, such as rafting, canoeing, and hiking.

The ridge of the Appalachians that the Delaware crosses is called the Blue Mountains in Pennsylvania and the Kittatinny Mountains in New Jersey. The New Jersey mountain is Mt. Tammany , the Pennsylvania mountain is Mt. Minsi . The summit of Tammany is 1200 ft (360 m) above the river. The Appalachian Trail threads the gap, and climbs the Kittatinies by a beautiful stream called Dunnfield Creek.

In the 1960s, a dam was almost built upstream of the water gap at Tocks Island. The Delaware Water Gap National Recreation Area was created for the planned reservoir.

Delaware Water Gap, Pennsylvania is the name of a town located near the gap.