Nestled just below the ridgeline that separates New Hampshire from Quebec, Fourth Connecticut Lake marks the humble beginnings of New England’s longest river. More than 400 miles long, the Connecticut River is also the largest watershed in the region, draining nearly 12,000 square miles of New Hampshire, Vermont, Massachusetts, and Connecticut, where it enters the ocean at Long Island Sound.

Fourth Connecticut Lake Preserve symbolizes the importance of the Connecticut River watershed while protecting important boreal habitats. At 78.1 acres, the preserve is surrounded on the U.S. side by an additional 4,900 acres protected by a conservation easement held by The Nature Conservancy and owned by the state of New Hampshire (part of the Connecticut Lakes Headwaters Natural Area).

The forest in the preserve is thick with balsam fir and peppered with red spruce, paper birch, and mountain ash, making it an ideal habitat for boreal birds like the northern three-toed woodpecker and spruce grouse, as well as woodland wildflowers like wood sorrel, bunchberry, creeping snowberry, and lady’s slipper. At 2.5 acres in size, the lake itself is considered a northern acidic mountain tarn, a small pond created by glacial action during the last ice age. Though shallow (it has a maximum depth of 5 feet) the pond does not completely freeze in winter and supports a small year-round fish population, river otter, and beaver.

High in the mountains of New Hampshire, you’ll find the Connecticut Lakes and headwaters of the Connecticut River. Starting as just a trickle in the small town of Pittsburg, the Connecticut River flows through a chain of lakes, the Connecticut Lakes, as it makes its way from the US-Canadian border in New Hampshire to Long Island Sound. Its journey of 400 miles begins at the height of land, becomes the diving border between Vermont and New Hampshire, then flows through the industrial valley of Massachusetts and into Connecticut before finding the sea.

The trail to Fourth Connecticut Lake heads west along the US-Canada border, at times climbing steeply. Please be sure to watch your footing. At 0.4 mile you will come to the preserve corner and eastern boundary. Remain on the international boundary trail another 0.1 mile until you come to the place where the Conservancy’s trail drops south from the international boundary. Follow this trail 0.1 mile to the north end of the lake, where you may choose either direction for a 0.5-mile loop walk around the entire water body. At the south end of Fourth Lake, you will literally step over the Connecticut River as it begins its great journey southward. Your return back along the international boundary trail will be easier, but watch your footing in steep and wet places. Take time to enjoy the views of the surrounding landscape as you crest the last knoll before the end of the trail. The entire round trip is 1.7 miles and usually takes about 2 hours.