Middlesex Fells Skyline Trail is a standout hiking destination in Medford, Massachusetts, covering 7.0 miles with 500ft of elevation change. Stats: 7.0 miles, 500ft gain, Moderate. Type: Loop. Surface: Rock/Dirt. Time: 3-4 hours. Fee: Free. Dogs: Yes. Permit: No. Wildlife: deer, foxes, coyotes, herons. Best seasons: Rugged ridge trail through the Fells near Boston. Pack water, layers, and appropriate footwear. Conditions vary across Massachusetts. Leave No Trace: stay on trail, pack out all waste, respect wildlife.