The Symingtons, upon the advice of Edward H. Bouton, the developer of the Roland Park and Guilford neighborhoods in Baltimore, hired landscape architect Frederick Law Olmsted Jr. to create a master plan for the island.

From that time to the present, the Corporation has had its own real estate department specifically handling the listing and selling of island properties.

This change led to a greater emphasis on maintaining the island's natural environment, with about two-thirds of its land set aside for recreation, forestry and open space.

Features of the island include a yacht club, golf, tennis, skeet shooting, a post office, a historical society, and an Episcopal church.

There have been reports over the years of sworn officers from the Anne Arundel County Police being stopped and questioned by the guards at the entrance to the island.