• Lush vegetation on the top of Spectacle Island's North drumlin dominates the foreground. Boston's skyline can be seen in the distance.  The park's logo with tag line minutes away, worlds apart empashises the stark contrast between the city and islands.

    Boston Harbor Islands

    National Recreation Area Massachusetts

Education Themes: Science & Technology

Water Quality

  • In the 1980s, Boston Harbor was considered one of the most polluted in the country. Since then, however, the Deer Island water treatment plant and clean-up efforts have led to a remarkable turnaround and the water quality is significantly improved. Plant and animal life, particularly on the sea floor, has rebounded and biodiversity is flourishing.
  • The Massachusetts Water Resource Authority's (MWRA) water treatment facility on Deer Island is the 2nd largest in the United States and has played a large role cleaning up Boston Harbor.
  • 370 million gallons of sludge—enough to fill the Prudential building 3 times—passes through the MWRA's Deer Island facility each day.

Lighthouse Technology & Use

  • Little Brewster is home to Boston Light, the oldest light station in the country, dating back to 1716.
  • The lighthouse uses a 2nd order Fresnel lens consisting of 336 individual prisms weighing 4,000 pounds. With this lens, the lighthouse's single 1,000 watt bulb is magnified to 20 million candlepower and is visible for 27 miles.
  • In addition to being an active light station, today Little Brewster is an active weather station for the U.S. Coast Guard.

Did You Know?

Graves Light

On September 1, 1905, Elliot Hadley lit the most powerful light in Massachusetts at the top of Graves Lighthouse, now in Boston Harbor Islands National Recreation Area. The first-order Fresnel lens aided in navigation and allowed for safe passage into Boston Harbor. More...