Nashoba Brook Subwatershed
Nashoba Brook is the largest tributary of the Assabet River and has a 
drainage area of over 48 square miles (this includes the area that drains into Fort Pond Brook, which joins Nashoba Brook shortly before the stream discharges into the Assabet). Nashoba Brook’s headwaters are in Littleton, near the Littleton Common, but the stream soon flows into Westford, where it goes along the northeastern edge of the Nashoba Valley Ski Area. This brook is fed by several smaller streams as it travels southeast toward Acton, then West Concord, joining with the Sudbury river at Egg Rock to form the Concord River. The Concord flows north through Carlisle, Bedford, Billerica, Lincoln, Westford, Tewskbury, & Chelmsford until it meets the Merrimack in Lowell.