The Concord River begins at the confluence of the Assabet and Sudbury Rivers in Concord and flows northward to join the Merrimack River in Lowell. The Upper Concord segment runs from the confluence northward to North Billerica, ending upstream of the Talbot Mills dam.
This segment, together with contiguous sections of the Assabet and Sudbury Rivers, was federally designated in 1999 as a Wild & Scenic River, reflecting its natural beauty and free-flowing quality (absence of dams). It contains the world-famous Minute Man National Historical Park managed by the National Park Service, the historic Old Manse owned by The Trustees, and the Concord Unit of Great Meadows National Wildlife Refuge managed by the US Fish and Wildlife Service. Historical records show that swimming was a popular pastime in the Upper Concord River.
The Upper Concord River received an Overall grade of B. The outstanding scenery received a grade of A. The grade of D for Fish Edibility is due to the mercury contamination from the Nyanza Superfund site on the Sudbury River upstream. Since the river is downstream of several dam systems, non-stop flows from wastewater treatment plants, and other human impacts, the streamflow is significantly altered from what it would be in its natural state, resulting in a Streamflow Alteration grade of D+.