The Cross River is a short river in southern New York State that rises near Cross River in the township of Lewisboro. After its rising point, it makes a loop, heading SE, then SW, then NW, and finally west. It flows a few miles in that direction until it ends up in the Cross River Reservoir, which supplies New York City with drinking water. It flows out of the spillway at the end of the reservoir, and continues further until it joins the Croton River in Katonah.
The short stretch of river that begins at the spillway outlet and continues on to the river's entry into the Muscoot Reservoir is an outstanding early spring trout fishery.