Headwaters of Halls Stream, New Hampshire

The international boundary at the top of New Hampshire transitions from the Highland ridgeline to Halls Stream, a nascent river that begins at this remote point in the woods.  This is considered the northwestern-most headwaters of the Connecticut River, and according to the treaty that defined the boundary (the Webster-Ashburton Treaty of 1842), the border was to follow the middle of this stream’s channel south until it intersected with the 45^th parallel, a distance of around 25 miles. Marking the border along this tiny, meandering stream is a major challenge for the International Boundary Commission, the agency tasked with placing the boundary accurately on the ground. Initial surveys in the 19^th century placed the line in the “middle of Halls Stream.” By the time it was resurveyed in 1908, the river had shifted more than 600 feet in some places. By 1979, more than half of the 467 turning points logged and marked with shoreline reference points along the stream were now on land. The recorded boundary meanders through what are now fields and meadows, often unmarked, and possibly even unknown to landowners, who assume that the boundary is still in Halls Stream, not in the middle of their lawn.