The Oak Square Firehouse in Boston was built in 1913 as a “Tapestry Brick” building. It was designed by Maginnis & Walsh, architects better known for their designs of Roman Catholic Churches. The station opened on February 24th as the home of Ladder 31. Seven years later, Engine Co. 51 was established, taking the place of Ladder 31, which was disbanded.

Over the 74 years that the firehouse was occupied, two other ladder companies operated from this location alongside Engine 51. Ladder 34 was stationed here from 1950 to 1954, and Ladder 22 operated from 1972 until being disbanded by Prop 2½ in 1981. 

In 2010 and 2011, Engine 51 was relocated to allow for the complete renovation of the firehouse. It was the only time an active fire company did not occupy the building. 

The Oak Square Firehouse is dedicated to Firefighter David A. Middleton, a member of Engine 51 who was killed in the line of duty at Box 5247 on May 29th, 2007.