Belle Isle Marsh Reservation in East Boston, Suffolk County, Massachusetts is an urban nature preserve and public recreation area containing mostly coastal wetlands.

It was once a Metropolitan District Commission reservation, but it is now run by the Massachusetts Department of Conservation and Recreation.

[4] The marsh is home to a wide variety of saltmarsh plants, marine life, and birds.

[6] Part of the island is now developed as Orient Heights; much of the remainder is Belle Isle Marsh.

Features of the reservation include landscaped hiking paths, benches, an observation tower, and handicap access.