Round Lake

Round Lake is the smaller of the two lakes at Green Lakes State Park and a National Natural Landmark, designated by the U.S. Department of the Interior in 1973. It is a meromictic lake over 163 feet deep and only about 700 feet across, ringed by old-growth forest. You can walk around it on the 0.9-mile Round Lake Trail, which is foot traffic only. Fishing and boats are not allowed on Round Lake.

Why Round Lake Is a National Natural Landmark

A National Natural Landmark is a natural area that the Secretary of the Interior recognizes as one of the best examples of the country's biological or geological features. The State Parks blog says Round Lake is one of 28 such sites in New York. Two things earned the designation: the lake itself, a rare meromictic lake, and the forest around it, which includes about 20 acres of old growth. The National Park Service lists the landmark at 100 acres in state ownership and calls Round Lake one of 11 meromictic lakes reported in the United States. A plaque at the lake marks the designation.

What Makes the Lake Unusual

Round Lake is deep for its size, and that is the whole story. With more than 163 feet of water under a surface only about 700 feet across, the wind cannot stir it to the bottom. The deep water never mixes with the surface, never gets oxygen, and holds few living things. See why the water is green for the science, and for why Green Lake, though also meromictic, was left out of the landmark.

Walking the Round Lake Trail

The NYS Parks trail map shows three short trails here, all marked grey or unmarked and all foot traffic only:

• Round Lake Trail (RL), 0.9 mile. The loop around the shore.
• Tween Lakes Trail (TL), 0.4 mile. The link between Round Lake and the south end of Green Lake.
• Round Lake Overlook (RLO), 0.5 mile. A higher route on the slope above the lake's north side, near the Cabin Colony.

Put the Green Lake Trail (1.9 miles), the Tween Lakes Trail and the Round Lake Trail together and you have the walk most visitors mean by "the lakes loop." The State Parks blog puts the full loop at approximately three miles, with benches along the way. See Green Lake Trail.

The Old-Growth Forest

The forest around Round Lake has had very little cutting over the past few centuries. The State Parks blog says it now holds trees from 100 to nearly 400 years old. Some of the tallest grow in the Tuliptree Cathedral, south-west of the lake, where a tuliptree measured 147 feet in 2011. See old-growth forest.

Rules at Round Lake

• No fishing. NYS Parks: fishing is allowed only on Green Lake, outside the swimming area. "No fishing on Round Lake."
• No boats. No outside boats, kayaks or canoes on either lake. Boat rentals are on Green Lake only.
• No bikes on the lake trails. The trail map marks the Round Lake, Tween Lakes and Green Lake trails as foot only.
• No swimming. Swimming is allowed only at the guarded beach on Green Lake.

Getting There

Round Lake is in the middle of the park, south-west of Green Lake. From the main entrance off Route 290, park in the lots near the beach and walk the Green Lake Trail south, or start from the Rolling Hills Camping Area and Cabin Colony on the lake's north-west side if you are staying overnight. See parking and the trail map.