Tri-State Trek">Tri-State Trek

Tri-State Trek

tri-state marker

tri-state marker


  • Distance: 4.25 miles (lollipop loop)
  • Level of Difficulty: Moderate
  • Town(s): Thompson, CT; Douglas, MA; Burrillville, RI
  • Property Owned By: State of CT, State of MA, State of RI
  • Hunting Allowed: Yes
  • Dogs Allowed: Yes


So much to see on this great hike! This is a lollipop loop that starts and ends at the site of the only 4-train collision in US history—no kidding. Four trains *BOOM*. There isn’t much there now except a kiosk with some photos and info about the crash. This hike also takes in 3 states and the tri-state marker on the borders of Rhode Island, Connecticut, and Massachusetts. There are also some very impressive old cellarholes, a “bossie crossing” trestle bridge over a railroad bed, and a mysterious hermit’s cave.

Trailhead is at Connecticut’s Air Line State Park Trail. This is the bed of a railroad that used to run between New Haven and Boston in a direct line, the way a crow would fly, hence the name. The first thing you see as you walk along the trail is a high wooden trestle bridge overhead. It’s a “bossie crossing,” i.e., a trestle bridge that allowed the farmer whose land was bisected by the railroad to get his cattle across the tracks. At about the 1/4-mile mark, a very short detour north from the trail takes you to the Hermit’s Cave, and old corbelled-stone root cellar. Then you have a choice of either continuing along the Air Line State Park Trail, which becomes the Southern New England Trunkline Trail (SNETT) once you cross in to Massachusetts, or taking a blue-blazed trail due south about 6/10ths of a mile in which will take you to the tri-state marker.

If you choose to visit the marker first, a warning: the trails past here aren’t blazed until you get to the Douglas State Forest in Massachusetts. From the marker you head due east along the Massachusetts/Rhode Island border for just about 1/2 mile, then take a left onto a trail headed north into Massachusetts. After about 1/4 mile, you’ll come to another intersection, and at that point you’ll see the yellow triangle blazes that mark the Massachusetts Mid-State Trail. By the way, don’t forget to check out the amazing cellar holes through this area. Go left, or north, and follow the yellow blazes until the Mid-State trail makes a hard right onto an old woods road. You go left.

Less than 1/4-mile along the old woods road takes you to the SNETT where you take a left back to your start.


  • If you’re a geography geek, the highlight is the tri-state marker (see photo, above).
bossie crossing

bossie crossing

  • This old wooden trestle bridge isn’t far into the hike.
Hermit's Cave, Outside

hermit’s cave entrance

  • Not sure how this got labelled “The Hermit’s Cave.” It certainly isn’t spacious enough to live in, but it would make a dandy root cellar. The method in which the stones are laid is called “corbelling.” The stones form a dome. Check it out, it’s really cool.
massachuetts mid-state trail marker

massachuetts mid-state trail marker

  • The Massachusetts Mid-State Trail starts at the Rhode Island border (which is also where the Rhode Island North-South Trail starts), and continues north to the New Hampshire border. This hike takes in a part of this trail.
amazing complex of cellar holes

amazing complex of cellar holes

  • Photos don’t do this group of old cellar holes justice. There must have been a substantial and prosperous farm here once.

On-line Resources (Links)