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 Lower Concord segment runs from North Billerica, upstream of the Talbot Mills dam, to where the Concord River joins the Merrimack River.
The Lower Concord River received an Overall grade of C+. This is the shortest segment in the watershed. It has urbanized land use, which is reflected in a Habitat grade of D+. Current work to improve trails, such as the Concord River Greenway and connections to the Bruce Freeman Rail Trail in Lowell, have the potential to improve the Recreation grade of C.