Deer Island (Massachusetts)

Deer Island is a peninsula in Boston, Massachusetts, formerly an island. It is located in Boston Harbor and is part of the Boston Harbor Islands National and State Park. Though connected to the mainland in 1916 by a narrow causeway, and further expanded by land reclamation over subsequent decades, it remains referred to as an island.

Deer Island is primarily known for being the location of the Deer Island Waste Water Treatment Plant (also known as the Deer Island Treatment Plant), operated by the Massachusetts Water Resources Authority (MWRA). This plant processes wastewater from the Boston metropolitan area. The plant's iconic "digesters," large egg-shaped structures, are a prominent feature of the landscape and are visible from many points around Boston Harbor.

Prior to its role in wastewater treatment, Deer Island served various purposes. It was used as a quarantine station in the 19th century, particularly during cholera and yellow fever epidemics. It also housed a poorhouse and an industrial school for boys. Tragically, it was the site of significant suffering and mortality, particularly among immigrants who were quarantined there under harsh conditions.

Today, alongside the wastewater treatment plant, Deer Island offers recreational opportunities. A perimeter path provides walking, running, and biking trails with views of the Boston skyline and the harbor islands. The island's history and environmental significance make it a unique and complex part of the Boston landscape.