Rancocas Creek is a tributary of the Delaware River, approximately 30 mi (48 km) long, in southwestern New Jersey in United States. It drains a rural agricultural and forested area on the eastern edge of the Pinelands north and northeast of Camden and the New Jersey suburbs of Philadelphia.
It rises in several branches in the Pinelands National Reserve. The North Branch rises in northern Burlington County, in Mirror Lake, just south of Fort Dix. It flows WNW past Mount Holly.
The South Branch rises in central Burlington County near Chatsworth and flows generally northwest. It receives the short Southwest Branch from the south approximately 5 mi (8 km) south of Mount Holly. The North and South branches join near Rancocas State Park, approximately 3 mi (5 km) west of Mount Holly, near the crossing of the New Jersey Turnpike and Interstate 295 (Delaware-New Jersey). A few hundred yards upstream of the Interstate 295 and NJ Turnpike bridges, Burlington County Route 635 passes over the Creek on a bridge built less than 4 feet over the average water level. This bridge has the capability for the center section of the bridge to swivel from the perpendicular to the river to parallel, to allow small boat traffic through. The bridge has rarely opened in the past 3 decades, however. The combined stream flows 5 mi (8 km) northwest past Willingboro and joins the Delaware from the east at Riverside, where it is crossed by the Riverside-Delanco Bridge.
It is navigable for approximately 10 mi (16 km) upstream from its mouth on the Delaware. However, the CR 635 bridge effectively places a barrier to boat traffic 5 miles upstream from the Delaware.
Fallen timber, brush, submerged riprap, inlets, coves.