The Air Line State Park Trail is a rail trail and linear state park located in Connecticut. The trail is divided into sections designated South (25 miles: East Hampton to Windham), North (21 miles: Windham to Putnam) a piece of the East Coast Greenway, and the Thompson addition (6.6 miles: Thompson to the Massachusetts state line). An additional 3.6 mile spur to Colchester is sometimes designated as part of the Air Line trail. At the Massachusetts state line, the trail connects to the Southern New England Trunkline Trail, a 22 mile long trail to Franklin, MA built on the same right-of-way. Since 2018, the town of Portland, CT has also maintained a 2.3 mile portion of the Airline Trail, connecting to the southern end of the state park at the town line with East Hampton.