There are four lakes: First, Second, Third and Fourth Connecticut Lake, numerically running south to north. The lakes decrease in size and increase in elevation, sequentially from first to fourth. The fourth lake is the source of the Connecticut River. The first three lakes can be viewed and accessed from U.S. Route 3, while the only access to the fourth lake is via the Fourth Connecticut Lake Trail, which goes in and out of Canada. All lakes are north of the 45th parallel.