Thompson Island (Massachusetts)

Cathleen Stone Island, also known as Thompson Island, is a 170-acre (69 ha) island in the Dorchester Bay section of Boston Harbor, offshore from downtown Boston, Massachusetts. It is located slightly more than 4 miles (6.4 km) from Boston's Long Wharf via boat,^[1] while approximately 1 mile (1.6 km) straight-line distance from Boston's Columbia Point.

The island is managed by the Cathleen Stone Island Outward Bound Education Center, a non-profit education organization. The island is open to visitors on Saturdays and Sundays from Memorial Day through Labor Day; otherwise access is by arrangement only. Cathleen Stone Island is one of the largest, most accessible and ecologically diverse islands in the Boston Harbor Islands National Recreation Area.^[1]

The island's highest point is a drumlin that reaches a height of 78 feet (24 m) above sea level. The rest of the island comprises low rolling hills and a salt marsh. The island has a mixed vegetation, including hardwood tree stands, remnant pear and apple orchards, ornamental trees and shrubs, and salt marsh grasses. The island has open meadows, forests, marine wetlands, sumac groves, and a variety of other geological features as well. Amenities include a formal school campus complete with classrooms, dormitories, dining hall, auditoriums, gymnasium, lab space, outdoor challenge courses, and climbing towers.^[1] At low tide, a sandbar connects it to the Squantum peninsula, allowing land travel between the two.