Fourth Connecticut Lake

Pittsburg, New Hampshire

Open to the Public


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What makes this place special?

A small glacial tarn, 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 preservet 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.

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.

How was this land protected?

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.

How can I explore this property?

To reach the lake, hike the 1.7 mile loop trail that heads west from the parking lot next to the border crossing station on US 3.  The trail is steep, rocky, and wet in sections as it follows the US-Canada border (notice the boundary signs written in French!) for 0.5 mile before it turns left and drops down to the shore of the lake.  Upon reaching the water, turn either right or left to follow the loop trail around the lake.  At the southern end of the pond, you'll cross a small stream that marks the very beginning of the Connecticut River   This is also a good spot to look for woodland wildlflowers in late May and early June. Continuing around the pond will bring you full circle back to the main trail where a turn to the right returns you to US 3.

As you enjoy the natural beauty of the preserve, you might feel worlds away from the industrial forestland that has defined this part of New Hampshire for more than a century.  This land was owned and managed by industrial timber companies for most of the 20th century, but its forest has not been harvested since 1916.  In the late 1980's, the Conservancy began a multi-state campaign to protect the Connecticut River's most ecologically significant sites, including floodplain forests, freshwater marshes, peatlands and other wetland and forested habitats near the river.  In 1990, Champion International generously donated the entire 78.1 acre watershed of Fourth Connecticut Lake to The Nature Conservancy in honor of Earth Day, a gift that proved to be both meaningful and symbolic to the campaign to protect the best of the Connecticut River.

While hiking through the woods here, note the many downed trees and snapped tree trunks – don’t worry, this is nature at work. Though protected from timber harvesting, the forest at Fourth Connecticut Lake regularly experiences natural disturbance.  In the mid and late-20th century, the area was subject to recurring cycles of spruce-budworm infestations, which is estimated to have killed about half of the conifers during the last outbreak in 1982.  The high elevation (2670 feet) exposes the forest to extreme weather where high winds, combined with thin, rocky soils, regularly blow down trees.  These disturbances are part of the natural cycle of a dynamic and regenerating forest, reshaping it into a diverse mix of trees of different ages, which provide habitat for a greater variety of flora and fauna.

Trail Maps and Other Information

Trail maps of the Fourth Connecticut Lake Preserve are available for download as well as at a small kiosk located at the preserve’s trailhead.

Special Visitation Guidelines

•    Foot travel only
•    No pets
•    No hunting, trapping, or fishing (due to the sensitive nature of the floating bog mat)




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!

Preserve Guidelines

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:

  • Foot travel only
  • No pets
  • Please carry out trash
  • No removal or destruction of plants, wildlife or
  • minerals
  • No camping or open fires
  • No hunting, trapping or fishing.

Route 3 North, 22 miles past Pittsburg village to the US/Canada border. Park across the road from the U.S. Customs station. The trail begins on the same side as the Customs station, about 50 yards on the right of the building. There's a small kiosk at the trailhead.


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