Places We Protect

Fourth Connecticut Lake

New Hampshire

Border divide marker on hike to TNC's Fourth Connecticut Lake Preserve in Pittsburg, N.H., which straddles the U.S.-Canada boundary.
Two Countries. One Conservancy Border divide marker on hike to TNC's Fourth Connecticut Lake Preserve in Pittsburg, N.H., which straddles the U.S.-Canada boundary. © Eric Aldrich/The Nature Conservancy

Straddling the border, this preserve in Pittsburg protects the headwaters of the majestic Connecticut River.



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 habitat. 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 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.



It may be wise to carry a passport when visiting this preserve.


A fascinating floating bog mat borders the pond – but please don't try stepping out into the bog, as you will likely damage the fragile flora and lose a boot in the process! The bog is home to a variety of grasses, sedges, mosses, and hardy low shrubs like leatherleaf. Look carefully and you’ll be able to see healthy populations of insectivorous plants like pitcher plant and sundew.  Both plants capture insects in order to access nutrients that are difficult to obtain through the acidic bog soils.


78.1 acres

Explore our work in this region

One of the first acquisitions in the Conservancy’s Connecticut River Campaign was the 1987 donation by Champion International Corporation of 427 acres at Norton Pool and East Inlet (also in Pittsburg). Three years later, Champion repeated its generosity by donating the entire 78.1-acre watershed of Fourth Connecticut Lake to the Conservancy in honor of Earth Day. Having long been the target of preservation by several environmental groups, this gift was meaningful and symbolic to the campaign to protect the best of the Connecticut River.

The Conservancy’s management goals are simply to preserve the natural character of the land and to provide for passive recreation, nature study and education. To that end, the Conservancy built the existing trail around Fourth Lake in 1995.

What to See: Plants

The edge of the lake is surrounded by a well-developed floating bog mat of mosses, sedges, grasses, leather leaf, the uncommon buckbean, and a large concentration of insectivorous plants, such as pitcher plant and sundew. The lake’s waters contain bladderwort, an aquatic plant with underwater bladderlike leaves that trap tiny aquatic creatures. The surrounding forest is fragrant with balsam fir. Other species include red spruce, white birch, and some American mountain ash. On the forest floor you are likely to see some northern wood sorrel, creeping snowberry, bluebead lily, and goldthread. Wildflowers abound at the southern end where the Connecticut River flows out of the lake.

What to See: Wildlife

This is a great place to see moose, beaver, waterfowl, spruce grouse, northern three-toed woodpecker and many other species.  The trick is to be quiet and patient.

Preparing for Your Visit

Wear sturdy hiking shoes. The trail is steep and can be wet and slippery in places. Bring a camera; you'll need it. When approaching Fourth Lake at the end of the trail, hike quietly; you might see a moose, beaver or river otter. That's when you'll need the camera!

Enjoy the Preserve Responsibly

This natural area is open to the public for recreation and education. Please, for the protection of this area and its inhabitants, and for everyone’s enjoyment:

•   Leave No Trace—please keep the preserve clean by carrying out your trash (and any that you find).

•   No camping or open fires allowed.

•   Please, for your safety and the protection of this ecosystem, stay on marked trails.

•   Foot traffic only; horses, bikes and motorized vehicles are prohibited.  

•   Pets are not permitted; help us protect wildlife on the preserve and be respectful of other hikers by leaving your pets at home.

•   Hunting, fishing and trapping are prohibited.  

•   Respect the natural world around you! Do not remove or destroy plants, wildlife, minerals or cultural items.