Prospect Hill (Somerville, Massachusetts)
Coordinates: 42°22′47″N 71°05′47″W / 42.3797°N 71.0964°W
Union Square is a neighborhood in the southeastern part of Somerville, Massachusetts. It is centered on Union Square proper, which is located at the intersection of Washington Street, Webster Avenue, and Somerville Avenue.
The name "Union Square" comes from the square having been used as a recruitment and mustering site for the Union Army in the American Civil War. A plaque commemorating the mustering site sits at the southwest corner of the square between Somerville Avenue and Washington Street, and the Prospect Hill Monument is located several blocks away atop Prospect Hill. Union Square is now the commercial center of a primarily residential neighborhood with many restaurants, bars and neighborhood stores.
As the oldest and largest commercial area in the city, Union Square is home to a number of community institutions, including the Somerville Police headquarters, Somerville Community Access Television (SCATV), and Boston Free Radio.
Union Square was Somerville’s earliest commercial district to develop when it was still a part of Charlestown. Early trade routes passed through the Square and a tavern was built there as early as 1770. Originally called "Sand Pit Square," the area's sandy, clay pit-dotted pastures yielded a fine grade of silica used in glass and brick-making.
It was during the American Revolution that Union Square took center stage. Because of its location and height providing panoramic views and control of Charlestown, Somerville, and Cambridge, Prospect Hill had great strategic importance in the Revolutionary War and became known as the "Citadel". The castle, dedicated in 1903, is a monument commemorating the fortifications atop the hill during that war. A tablet inside reads: "This tablet is erected in memory of the soldiers of the Revolution and of the Civil War who encamped on Prospect Hill and of the banners under which they valiantly fought."
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