(Most recently updated 07/19/2020.) The north terminus of US 3 is at a border crossing leading to Chartierville, Quebec. Since there is no town nearby on the American side, US 3 is often described as ending in Connecticut Lakes, New Hampshire. This is the name applied to the state forest that protects the upper reaches of the Connecticut River, where a chain of lakes is situated near its source. US 3 goes right past three of them:
But did you know there is also a Fourth Connecticut Lake? This lake (actually a small pond) is the true source of the Connecticut River. It is not situated directly on US 3; in fact, it is not accessible by any road. Instead, visitors park at a trailhead right across from the U.S. border inspection station.