The park is strikingly scenic, and has a "masterpiece"[2] golf course designed by Robert Trent Jones very early in his career.

[3] The park preserves the largest stand of old growth forest in Central New York,[4] and Round Lake has been designated as a National Natural Landmark by the U.S. Department of the Interior.

[7] Nearly half the park's area is old-growth forest,[4] which includes many very large specimens of tuliptrees, sugar maples, beech, basswood, hemlocks, and white cedars.

Of this region, Mary Notarthomas has written that "When walking on the lake trails, one is cradled between the rich, vibrant, almost alien blue-green waters on one side and thickly vegetated, steep wooded inclines on the other.

The Erie Canal, which was abandoned in 1918, is still continuous within this State Historic Park, and the old towpath is now a walking and bicycling path.

The Park extends 36 miles (58 km) from the Butternut Creek aqueduct in DeWitt to the Erie Canal Village, which is near Rome.

Green Lakes State Park has an 18-hole public golf course designed by Robert Trent Jones in 1935.

He'd invited Gene Sarazen to play an exhibition match with Emmett Kelly, the first course pro; more than 1,000 people came to watch.

[11][12] James Dodson has written of the course that "the original little masterpiece at Green Lakes, where Wendy and I and sometimes the other Dewsweepers slipped away to chase the game among the gloriously mature evergreens and admire the long view over a dark blue glacial lake, to the very foothills of the Adirondacks themselves, remained just about my favorite Trent Jones golf course of all.

[13] Knapp, a descendant of the family that acquired and farmed this area in the early 19th century, noted the particular role of Harry Francis, then a professor at the New York State College of Forestry at Syracuse University (now the State University of New York College of Environmental Science and Forestry).

[14] In 1929, the Administration Building was built according to plans by Laurie D. Cox, a prominent landscape architect (and Hall of Fame lacrosse coach) who was active in the design of several New York state parks.

[12][16][17][18] The CCC camp was reopened in 1944 during World War II to house wartime farm workers from Newfoundland.

[26] Alverna Heights, a 200-acre retreat adjoining the park, was purchased from the Sisters of St. Francis by New York State on December 6, 2019.

[27] In 2008, the bathhouse near the park's swimming area and beach was demolished, and a new building was constructed to replace it at a cost of about $2.3 million.

[30] This deep gorge was formed towards the end of the last ice age, about 15,000 years ago, by an enormous river of water.

[35] The notable shoreline "reef" at Deadman's Point (see photo) on Green Lake was built up by this precipitation over thousands of years.

The meromictic character of the lakes is due both to their relative depth compared to their area, and to the influx of mineral rich ground waters.

Because of this lack of physical mixing, as well as the absence of growing plants or crawling animals in their oxygen-depleted depths, the deep bottoms of the lakes have relatively undisturbed annual layers of sediment (or varves) that preserve a historical record, somewhat like tree rings do.