The state of Massachusetts requires that ATV operators must be 18 years of age or older, unless they have completed one mandatory session of an approved recreation vehicle safety and responsibility course. They must do this in the company of a parent or guardian. Those completing this session may operate an ATV at 16 and 17 years of age. Fourteen through 16-year-olds may operate an ATV with an engine capacity of 90 cubic centimeters or less.
Check out these Brookfield, MA ATV/OHV resources:
