In 1874 George A. Stoughton petitioned and was granted a charter to open a bank. The first deposit was made in the department store of Burr and Stoughton, where the Bank first had its quarters.

When David Merriam made that first deposit, Thomaston was still officially part of Plymouth and called Plymouth Hollow. After a stormy legislative controversy, the village was called "Thomas-town". The controversy was finally resolved in 1875 in favor of a newly incorporated Thomaston.

After an interval, Thomaston Savings Bank left its corner in Stoughton's store and had the use of a small building owned by Seth Thomas. Miles Morse, the Bank's first president, built the block next door and designated a room where Thomaston Savings Bank remained until 1878. The bank then moved to the Woods Building at the corner of East Main Street and Electric Avenue. In October of 1889 the Bank moved to the Town Hall Building.

In 1939 the Board of Directors decided that the Bank should have a building of its own. The architect, Thomas M. James Company of Boston, chose the colonial style for the bank as an expression of the high character of the community, as well as those fine New England characteristics of honesty, stability, and thrift.

The Bank remained at 140 Main Street until November 1990, when it out grew this building and built a new corporate headquarters almost across the street. The Board of Directors voted to stay with the traditional colonial style as it had in the past.

In addition to our main office Thomaston Savings Bank now has seven branch locations. Our Watertown office opened October 1951, Terryville office opened October 1961, Harwinton office opened March 1975. Our Bethlehem branch opened June 1995, after a larger bank closed its branch. The South Main Street office, also located in Thomaston, opened January 1998 is conveniently located off exit 38 off route 8. Our Waterbury office, opened in October 2001. The Middlebury Office opened In April 2007 located at 1655 Straits Turnpike.

Commercial Lending  and Consumer Lending are now located in the newer portion of the corporate building which was completed in March of 2007.