The Sudbury River is a 32.7-mile-long tributary of the Concord River flowing through Middlesex County, Massachusetts. This picturesque waterway originates in Cedar Swamp in Westborough and meanders northeast through several communities before joining the Assabet River at Egg Rock in Concord to form the Concord River. In April 1999, nearly 17 miles of the river were designated as part of the National Wild and Scenic Rivers System for their outstanding ecology, history, scenery, and recreational value. The river offers diverse fishing opportunities with a variety of game fish in settings ranging from slow-moving sections with abundant vegetation to more open water areas.