Cow Yard Brook is a very short stream in central South Brunswick, New Jersey, and a tributary of Oakeys Brook. It begins near the intersection of Beekman Road, Northumberland Way, and U.S. Route 1, then flows east through a developed part of the township. On its brief course it crosses Deans Lane near Black Horse Lane, passes under Black Horse Lane, and joins Oakeys Brook near Black Horse Lane and Henderson Road. The brook’s location and crossings make it most readily reached from the roads along its route and from Oakeys Brook itself.