The Seth Thomas Clock Company was organized as a joint stock corporation on May 3, 1853 to succeed the earlier clock making operation of the founder. Seth Thomas (1785-1859) had been manufacturing clocks at the site since 1814.

After Thomas’ death in 1859, his son Aaron became President and began to add new products to a conservative line. About 1862, the firm purchased the patent rights of Wait T. Huntington and Harvey Platts of Ithaca, New York and added three models to their line that year. The earliest of the clocks indicate only three patent dates on the dials, September 19, 1854, November 17, 1857 and January 31, 1860. The fourth and final patent of March 1, 1862 is carried on most of their calendar clocks manufactured until 1875 or 1876. On February 15, 1876 Randall T. Andrews, Jr., a Thomas relative and workman in the factory, received a patent on an improved mechanism. This was put into production and utilized on all later perpetual calendar clocks until the last model was dropped in 1917.

The Seth Thomas Clock Company was very prosperous into the 20th Century and was considered the “Tiffany’s” of Connecticut clock manufacture, even by their competitors. Between 1865 and 1879 they operated a subsidiary firm known as Seth Thomas’ Sons & Company that manufactured a higher-grade 15-day mantel clock movement and during that period were major supporters of a New York sales outlet known as the American Clock Company. They also became a major manufacturer of tower and street clocks after 1872 and in between 1915 were manufacturers of jeweled watches.

On January 1, 1931, the firm became a subsidiary of General Time Instruments Corporation and soon passed from family control. The firm’s decline was gradual over the next 50 years and culminated in the firm’s removal from Connecticut to Norcross, Georgia about 1975. It was reported in 1988 that the firm was all but dissolved and, in 2003, the in-house collection of the firm was sold to private collectors.