Sand Pit Square 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. The castle, dedicated in 1903, is a monument commemorating the fortifications atop the hill during that war. Somerville is one of several municipalities claiming to have hosted the first raising of the
Continental Union Flag (the
flag of the
United Colonies from 1775 to 1776 and
de facto flag of the United States until 1777, when the
13 star flag was adopted). Tradition claims
George Washington raised it on Prospect Hill on January 1, 1776, and a plaque there indicates such. Since a favorable pardon was then being offered to the rebelling colonists, the raising of a flag similar or identical to the Union Flag was briefly mistaken for a gesture of allegiance to the Crown.
Industry growth in 1911 In its early years, Somerville was an agricultural suburb, supplying the growing urban area surrounding Boston. For a time the Union Square area was known as Milk Row after the small farms surrounding it. It became a meat packing and manufacturing district, with a
slaughterhouse,
brickyard, glass shop, and later other industries. In 1917, the first
Marshmallow Fluff to be sold in stores was produced in Union Square. In honor of this, since 2006 an annual Somerville Fluff Festival has been held in Union Square. Service to the Union Square railroad station ended in 1938, as some local stops on the
Fitchburg Railroad were dropped due to competition from streetcars. By then, Union Square was well served, first by
Boston Elevated Railway streetcars, then by buses.
Commerce and gentrification Like much of Somerville, Union Square suffered economic decline in the 20th century as wealthy residents moved to more distant suburbs and manufacturing moved away from the area. The city began planning for a revitalization of Boynton Yards in the 1980s, including the construction of South Street to allow trucks to serve lots once only reachable by rail. The city approved a cluster of four life sciences laboratory-office buildings (the first in Somerville), of which 101 South Street opened in 2022, 808 Windsor is expected to open in 2024. With rents lower than nearby Cambridge, Union Square attracted new immigrant populations towards the end of the 20th century, including large groups of Brazilian, Punjabi, and Sikh residents. Many markets in the area are run by and cater to the various ethnic groups that live in and around Union Square. Union Square's location at the juncture of working-class East Somerville and the city's tonier western sections have made it the focal point of changing demographics. More upscale cafes, bars, and restaurants have opened since the 1990s, bringing
gentrification deeper into Somerville.
Union Square Main Streets, a local development group, began running a Saturday morning
farmers' market in 2005 as one of its first visible efforts in the square. A landscaped community garden with regularly scheduled concerts and artistic events sits just outside Union Square at the site of an old school. ==Transportation==