District Lodge 91 received its charter in May 1953. At that time the representative locals consisted of Hartford Aircraft Lodge 743, chartered in 1941, representing workers at Hamilton Standard (located in East Hartford until 1952 when it moved to Windsor Locks); Industrial aircraft Lodge 1746, chartered in February, 1945, representing workers at Pratt and Whitney, East Hartford; and Industrial Aircraft Lodge 1746A, chartered in October, 1951, representing Pratt and Whitney workers in Southington. In March 1959 Canal Lodge 700, in Middletown, was chartered and added to District 91 representation. Prior to 1953, Pratt and Whitney workers' lodges were part of IAM District 26. As of 1984, District 91 included Lodge 700, Lodge 707 (from North Haven), Lodge 743, Lodge 1746, and Lodge 1746A.
The United Brotherhood of Carpenters and Joiners was founded on 8 August 1881. In 1892, sixty-eight carpenters in the Stamford area, dissatisfied with low wages and long workweeks, agreed to join the union. With the assistance of Frank Duffy, president of the New York UBCJ Council, UBCJ Local 210 of Stamford was organized. The charter was granted on 14 October 1897.