The Manumuskin River flows through a relatively pristine forested area in the southern Pine Barrens of Cumberland County, as well as Atlantic white cedarbogs and salt marshes in its lower reaches. The name is of Lenape origin.
It rises approximately 5 miles (8 km) east of Vineland and flows south-southwest, joining the navigable estuary of the Maurice from the northeast approximately 5 miles (8 km) south-southeast of Millville and approximately 7 miles (11 km) upstream from the mouth of the Maurice on Delaware Bay.
Approximately 3,500 acres (1,400 ha) of the watershed of the river are included in the Manumuskin River Preserve, established in 1983, the largest conservancy of its kind in New Jersey. Parts of the river are also designed as part of the Maurice Wild and Scenic River.
^U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. The National MapArchived 2012-03-29 at the Wayback Machine, accessed April 1, 2011