There are three good parking options.
Callahan State Park is a 958-acre day use area located in Northwest Framingham and the City of Marlboro with a mix of well-maintained fire roads, walking trails and singletrack. It was named in honor of Raymond J. Callahan, a former local newspaper editor, by an act of the Massachusetts legislature in 1971. The park is managed by the Department of Conservation and Recreation. Callahan has nearly 100 acres of open fields, 70 acres of which are under an agricultural lease. The Bay Circuit Trail cuts through Callahan and can make for a fantastic endurance ride.
Callahan State Park is a great haven for dog owners and occasional equestrians, who pursue the open space with the same vigor and respect as MTB riders. Much of the property allows owners to run their dogs run off leash.
The park abuts, and in some cases envelops land owned by Sudbury Valley Trustees (SVT). Biking regulations vary depending on land ownership, and it is not always evident who the property owner is when biking. In most sections, it is clearly marked where biking is not permitted. The SVT map in the link below shows SVT trails were biking is permitted.
For a fun introductory ride to the park, start at the Millwood Parking area. Enter left onto the large earthen dam. Follow any of the outer perimeter trails and make your way to Red Tail Trail. Cross Edmands Road carefully, as traffic can be fast, and spin up Gibbs Mountain. Find your way to the Backpacker trail and follow to the Broad Meadow Rd parking area. Bike the southern trails back to Edmands Road and continue to the Edmands Road Parking area. For a hill climb take the Pipeline trail and make your way back to the Millwood Road Parking area. To avert the climb take Pioneer trail to Rocky Road and make your way back to the parking area.
Two hills worth climbing are the Pipeline trail near the Edmands Rd parking lot and Gibbs Mountain.Park Directions:
There are three primary parking areas: Millwood Street in Framingham, Edmands Road in Framingham and Broadmeadow Road in Marlborough. Millwood and Edmands are closer to the majority of trails and are recommended for a first time visit. The Millwood area can fill on days with great weather. Nearby Edmands Road parking almost always has plenty of space. 203 Millwood Road:
Rt. 9 west to Rt. 30 exit, right at first set of lights to Edgell Rd for .6 miles to Belknap Rd (left) for 1.1 miles, right onto Millwood St for .7 miles to entrance on left across from golf course.1031 Edmands Road:
Rt. 9 West, Right on Maynard Rd for .5 miles, Slight left on Grove St, Continue for 3 miles, Left on Edmands Rd. for ¾ mile. Parking will be marked on your left.241 Broadmeadow Road:
Rt. 9 West, Right on Maynard Rd. for .5 miles, Slight left on Grove St., Continue for 3 miles, Left on Edmands Rd. for 1.3 miles. Straight on Parmenter Rd for 1.5 miles. Turn right on Broadmeadow St. Continue for .3 miles to parking area by kiosk
SVT Map- Biking permitted SVT land is shownhttp://www.sudburyvalleytrustees.org/sites/default/files/NWFramingham.pdf