|Mary Elmer Lake|
|Location||Hopewell Township / Bridgeton, Cumberland County, New Jersey|
|Catchment area||7.5 sq mi (19 km2)|
|Basin countries||United States|
|Surface area||22 acres (8.9 ha)|
Mary Elmer Lake Dam is of earthen construction, a gravity dam, with a height of 15 feet (4.6 m) and a length of 500 feet (150 m). Maximum discharge is 4,078 cubic feet (115.5 m3) per second. Normal storage is 68 acre feet (84,000 m3). It drains an area of 7.5 square miles (19 km2). The lake is fed by Barret's Run, and the lake's water empties via a small stream into nearby Sunset Lake and thence into the Cohansey River.