Delaware River - Course

Course

The West or Mohawk branch rises in Schoharie County, New York, about 1,886 feet (575 m) above sea level, near Mount Jefferson, and flows tortuously through the plateau in a deep trough, impounded at one point to create the Cannonsville Reservoir, and then becoming the state boundary of New York and Pennsylvania at the 42nd parallel, until it emerges from the Catskills.

Similarly, the East Branch begins from a small pond south of Grand Gorge in the town of Roxbury in Delaware County, flowing southwest toward its impoundment by New York City to create the Pepacton Reservoir, the largest reservoir in the New York City water supply system. Its tributaries are the Beaver Kill River and the Willowemoc Creek which enter into the river ten miles (16 km) before the West Branch meets the East Branch. The confluence of the two branches is just south of Hancock.

Both the East Branch and West Branch of the Delaware River parallel each other, both flowing in a southwesterly direction.

From Hancock, the river flows between The Poconos and the lowered shale beds north of the Catskills. The river flows down a broad Appalachian valley, passing Hawk's Nest overlook on the Upper Delaware Scenic Byway. At Port Jervis, New York, it enters the Port Jervis trough. At this point, the Walpack Ridge deflects the Delaware into the Minisink Valley, where it follows the southwest strike of the eroded Marcellus Formation beds along the Pennsylvania–New Jersey state line for 25 miles (40 km) to the end of the ridge at Walpack Bend in the Delaware Water Gap National Recreation Area.

The Minisink is a buried valley where the Delaware flows in a bed of glacial till that buried the eroded bedrock during the last glacial period. It then skirts the Kittatinny ridge, which it crosses at the Delaware Water Gap, between nearly vertical walls of sandstone, quartzite, and conglomerate, and then passes through a quiet and charming country of farm and forest, diversified with plateaus and escarpments, until it crosses the Appalachian plain and enters the hills again at Easton, Pennsylvania. From this point it is flanked at intervals by fine hills, and in places by cliffs, of which the finest are the Nockamixon Rocks, 3 miles (5 km) long and above 200 feet (61 m) high.

At Trenton there is a fall of 8 feet (2.4 m). Below Trenton the river flows between Philadelphia and New Jersey before becoming a broad, sluggish inlet of the sea, with many marshes along its side, widening steadily into its great estuary, Delaware Bay.