Porter Square is the town square for several flourishing neighborhoods along Massachusetts Avenue from Cambridge Common to the Arlington line, with an exceptionally vibrant food scene, extensive retail options and part of the Lesley University campus.
Porter Square is reachable by MBTA Red Line, the 83, 87 and 96 bus lines, and the Fitchburg Commuter Rail Line.
History of Porter Square

Previously called Union Square, Porter Square was renamed in 1899 for Zachariah B. Porter, the larger-than-life owner of the Cambridge Cattle Fair Hotel (later: "Porter’s Hotel"). Porter also gave his name to the hotel's specialty, the cut of steak known as "porterhouse." (1. More on Porter and his hotel. 2. More on "Old Zach's" legal issues.) The hotel was demolished in 1909.
The square, formerly flanked by cattle yards that used the square's rail head to transport their beef throughout the country, was an important center for commerce and light industry as early as the late 18th century. A tunnel for moving cattle to and from the railroad without interfering with street traffic, known as the Walden Street Cattle Pass, was built in 1857. The tunnel survives under the nearby Walden Street Bridge, and in 2007–08 was preserved and restored.

From 1821, a two-acre park-like estate of the Rand family was a landmark of the area, and featured well-tended wide lawns, gardens, and winding footpaths for the neighborhood. In 1950, Mabel Rand, last of the family line, bequeathed the estate to the city as a park but the city refused the bequest, and in 1952 executors sold the property to developers who opened the Porter Square Shopping Center, which soon replaced the old business district near the corner of Mass Ave and Walden Street.

In 1984 the MBTA Red Line was extended from Harvard through Porter and Davis Square to its present terminus at Alewife. Susumu Shingu's 46-foot painted steel and aluminum kinetic sculpture entitled "Gift of the Wind", sits at the MBTA entrance.

In 2004–06 the city re-designed Porter Square's principal intersection, including the area adjacent to the shopping center, attempting to improve access for vehicles, pedestrians, and bicyclists.
In 2025, the Community Development Department released the Mass Ave Planning Study outlining how they see Porter Square and the Mass Ave corridor north and south of Porter Square evolving over the next ten to fifteen years.
www.cambridgema.gov/-/media/Images/CDD/Planning/massaveplanningstudycam…