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?
Constructed in 1716, Boston Light on Little Brewster Island is the oldest lighthouse site in the country. British forces burned down the original lighthouse when they fled Boston in 1776. It was rebuilt in 1783 and is now open for visitors to Boston Harbor Islands National Recreation Area. More...