Artificial lakes
The Ramapo River is a tributary of the Pompton River, approximately 30 mi (48 km) long, in southern New York and northern New Jersey in the United States.
The Ramapo River rises in Round Lake, a small lake in the Town of Monroe, New York, in a mountainous area of central Orange County, New York. It flows southeast through the village, where the river was dammed in 1741 for a sawmill and grist mill. It continues to Harriman, where a chemical plant, Nepera Chemical, was built. While the plant has been dismantled, a superfund site has been designated at the location where barrels of toxic chemicals were buried.
At Harriman, the river turns south into western Rockland County, where it flows through the hamlet and town of Ramapo, New York, then into northern Bergen County, New Jersey.
In New Jersey, it flows southwest along the east side of the ridge of the Ramapo Mountains. Following a course that runs above the Ramapo Fault for about 9 mi (14 km), the river then flows into Potash Lake in Oakland, and from there into Pompton Lake in Pompton Lakes. The river then flows out of Pompton Lake, forming the border between Pompton Lakes and Wayne.
The Ramapo forms a confluence with the Pequannock River along the border between Pequannock and Wayne, forming the Pompton River, which eventually flows into the Passaic River.
