Tibbetts Brook, originally Tippett's Brook or Tibbitt's Brook, is a stream in the southern portion of mainland New York, flowing north to south from the city of Yonkers in Westchester County into the borough of the Bronx within New York City. Originally emptying into Spuyten Duyvil Creek as part of the Harlem River system, the stream is now partially subterranean, ending above ground at the south end of Van Cortlandt Lake within Van Cortlandt Park. There it proceeds into city sewers, draining into either the northern end of the Harlem River or the Wards Island Water Pollution Control Plant. The brook provides significant watershed to both Van Cortlandt Park at its south end and Tibbetts Brook Park at its north end. There have been modern proposals to daylight the southern portion of the br