The trails here are a mix of double tracks (service roads) along powerlines, fire roads and single track. Riding along the powerlines is nice as it gets you out of the trees and on a more hard packed surface.
These trails are along on the Ayer - Groton townline. Parking can be found on Washington Rd (Ayer, MA) where the powerlines cross and on Sandy Pond Td (Groton, MA) also where the powerlines cross
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