Over the years, Sagamore Hill has managed to retain a degree of the natural character that it possessed when Theodore Roosevelt called it home (1887 to 1919). But only 35 miles from New York City, the site can not escape the influences of the urban and suburban environments that surround it. When Roosevelt first visited here, Cove Neck, a one mile wide and three mile long jut of land into Long Island Sound was open hay fields, under cultivation since the early 1700s. Today, over 95 percent of the land area is residential with highly maintained lawns and second growth forest.

Despite these pressures, Sagamore Hill boasts several valuable communities, including a relatively rare, intact stand of native oak-tulip tree forest, as well as a hydrologically intact maritime complex consisting of high and low salt marshes, a tidal creek, dunes, and beach.  

Due to its small size, Sagamore Hill does not contain large, contiguous areas comprised of a single vegetation type, but the site’s many vegetation types are utilized by a variety of plants and animals, including some locally and nationally rare species.  The park can best be considered an important part of the larger landscape needed to support viable wildlife populations.  For instance, the park’s beach-saltmarsh-tidal creek habitat complex is a component of the larger Oyster Bay and Cold Spring Harbor system, and as such, the provides an important nesting area for one of the larger populations of diamondback terrapins in the state.