The sizes of the islands in the park change every hour, as the ocean tides ebb and flow on their shores. All totaled, the park islands change from 1,483 to 3,067 acres during the tidal cycle. Learn how island acreage was measured, considering daily tides.
The names of several islands have also changed over time. How we selected the spelling of island names, and alternate names for some islands, are described in, "What's in a name?"
Choose an island below for details about each of the islands in the park. The topics shown are size, location, managing agency, facilities, natural history, historical sketch . . . and more.
Did You Know?
Boston Harbor Islands National Recreation Area offers great birdwatching of native and migratory bird species, including Oystercatchers, Least and Common terns, Common eiders, Cormorants, Brant, and Snowy owls. More...