Near Baldwinville, the 12,788 acre Otter River State Forest has miles of trails through hardwood and pine forests.
To reach mountain biking at the forest, follow SR2 west to Exit 20. Turn right onto Baldwinville Road and follow to end. Turn right onto SR202 heading north. Follow 202 north 1.2 miles to the park entrance on the left.
Overall, Otter River State Forest is the 27th most popular mountain bike trail of all 35 mountain biking rides in Massachusetts.