Pocantico River

Pocantico River
The Pocantico as it flows through Rockefeller State Park
Country	United States
State	New York
Region	Hudson Valley
County	Westchester
Tributaries
- left	Rockefeller Brook
- right	Caney Brook, Gory Brook
City	New Castle, Briarcliff Manor, Mount Pleasant, Sleepy Hollow,
Source	Echo Lake
- location	New Castle
- elevation	325 ft (99 m)
- coordinates	41°10′48.2″N 73°48′36.2″W / 41.180056°N 73.810056°W / 41.180056; -73.810056
Mouth	Hudson River
- location	Sleepy Hollow
- coordinates	41°5′29.5″N 73°52′12.9″W / 41.091528°N 73.870250°W / 41.091528; -73.870250Coordinates: 41°5′29.5″N 73°52′12.9″W / 41.091528°N 73.870250°W / 41.091528; -73.870250
Length	9 mi (14 km)
Discharge	for Rockefeller State Park
- average	37.19 cu ft/s (1 m3/s)
- max	77.3 cu ft/s (2 m3/s)
- min	15 cu ft/s (0 m3/s)

The Pocantico River is a nine-mile-long (14 km) tributary of the Hudson River in western central Westchester County, New York, United States. It rises from Echo Lake, in the town of New Castle south of the hamlet of Millwood, and flows generally southwest past Briarcliff Manor to its outlet at Sleepy Hollow. Portions of the towns of Mount Pleasant and Ossining are within its 16-square-mile (41 km²) watershed.

Writer Washington Irving, who lived in the area for most of his life, was inspired by the undeveloped area above the river's mouth to write his classic "The Legend of Sleepy Hollow". Later in the 19th century much of the land was purchased by the Rockefeller family as part of their Kykuit estate; today much of that land has become Rockefeller State Park Preserve. A former reservoir used by the city of New Rochelle has likewise been converted into county-run Pocantico Lake Park. While the river runs predominantly through those parks and suburban land, it is still one of the most polluted tributaries of the Hudson.

In the past the Pocantico was considered to have two different sources, but today it is acknowledged that it rises from Echo Lake in the eponymous state park located in the town of New Castle between Saw Mill River Road (New York State Route 100) and the Taconic State Parkway, just southwest of the unincorporated hamlet of Millwood. The lake is 325 feet (99 m) above sea level, in a narrow valley between Cabin Ridge to the east and a similarly steep ridge on the west. Its surrounding terrain is primarily wooded and lightly developed outside of the two roads. The river begins at a dam on the lake's south end.