The 1,520-acre (6.2 km2) park[2] covers the former Marshall Field III estate that was developed in the 1920s, and was listed on the National Register of Historic Places in 1979.

Much of the park is today managed as a nature preserve, with a focus on protecting high-quality bird habitat.

The "Caumsett Bird Conservation Area" was established in 2006 and comprises approximately 1,255 acres (5.08 km2) of the state park, two-thirds of which is forested.

The designated area protects high-quality habitat that supports breeding populations of several species listed as threatened or endangered in New York State, including piping plovers, common terns, and least terns; many additional migratory species also make use of the protected landscape.

[12] The park allows for recreation such as horse-riding, fishing, jogging, hiking, biking, and cross-country skiing.