The Hutchinson River is a freshwater stream located in the Bronx, and Southern Westchester County, New York. The river forms in Scarsdale at Brookline Road and flows 10 miles (16 km) south until it empties into Eastchester Bay in the New York City borough of the Bronx.The river provides the basis for the jagged city line at the north-west of New Rochelle, where it abuts Scarsdale and then Eastchester; further downstream and south, it plays a similar role between Mount Vernon and Pelham.