In January 1968, a group of Thompson residents, led by John Flood, met to form a historical society, interested in preserving Thompson records, artifacts and buildings.

The first annual meeting was held July 23, 1968 with the purpose to enroll members, elect directors and officers and to conduct the business of the society. The first officers were: President Elmer White, Vice President John Flood, Secretary Ann Davis and Treasurer Raymond Graham.

Meetings were held in the Thompson Memorial School cafeteria and, later, in different areas of the town including the West Thompson Fire Station, Quinebaug-Fabyan Community Center to name a few.

A committee was named to approach the town to purchase the Old Town Hall to use as a meeting place and a repository for donated historical artifacts. From the beginning, the Town of Thompson has been very supportive of the Society. The town voted a yearly stipend of $500. The Village Improvement Society also made donations including $200 for paint.

In 1969, the deed to the Old Town Hall was turned over to the Society for $1.00 which Merrill Seney, the Town Clerk, paid from his own funds. This began the long process of getting the building in shape. Ann Davis spearheaded this project, working to secure grants and directing improvements. All members of the Society for the year 1969 were considered charter members. Funds were raised by having two raffles. The prizes were paintings done by artist Vera Peterson and Sheila Burns.

Over the years, the Society has held or contributed to many events. In 1972, a 3-day town-wide spring festival, sponsored by the Society, was held, titled "A Walk Through History". Walking tours were held at important sites around town. In 1974, an oral history project was undertaken by the Thompson Library and the Society. A historical marker was dedicated on the Common in 1975, the result of a project led by Nancy Kriz. In 1976, an antique show was held, led by chairman Camille Strong. In 1977, Ruth Barks, chairperson, led another Walk Through History.

Work had progressed on the Old Town Hall to the point that it was ready by 1977 for meetings and events. The Christmas Concert, organized in 1989 by Jane Vercelli and held for 14 years at the Old Town Hall, was a smashing success, in part due to the intimate setting of the hall. The Old Town Hall has been the site of the Society's Museum Shop, which opened in 1990.

Activities in 1990s such as the Paine - Kwiecien auction, Garden Tours, Quilt Shows, Illumination Night Concerts and Society presentations of historical topics have all contributed to the Society's reputation as an active and contributing group to Thompson culture.

In 1995, the Society leased the former library on Thompson Hill from the town for a period of 99 years at $1.00 per year. Since then, the library, now called the Ellen Larned Memorial Building after Thompson's most famous historian, has been in the process of restoration by the Society. Under former Society President Jane Vercelli's leadership, the Society was recognized by the town for its significant accomplishments and was named the town's official municipal historian.

In 2000 the tradition of community involvement continued. Patriot's Day weekend was a tremendous success. Thompson's efforts, led by THS President Dave Babbitt, contributed to the march commemorating the militia's march to Bunker Hill for action against the British in 1775. With fife and drum corps leading the way, soldiers in period costumes marched to and encamped on Thompson Common. The proceedings were spectacular to behold and an excellent memorial for the Millennium year. Other Society activities in town included a speech by former Selectman Jim Sali, the release of a 25th Anniversary Calendar and a Millennium CD filled with photos and documents of Thompson's past.

Under THS President Joseph Iamartino, the progress continues with additional CD volumes, publication of a hardcover book of Thompson photographs called “Echoes of Old Thompson” and numerous presentations open to all, including talks on Lithic Structures in New England, Jim Canty and Sports in Thompson, Open Space and Conservation in Thompson to name just a few. Under the leadership of Beth Greene, a dedicated team of volunteers opened in 1993 the Ellen Larned Memorial Building as an on-going exhibition center documenting Thompson's history. The first exhibit featured the story of Thompson’s last country doctor Dr. Robert C. Paine. Significant changes in the Society’s mission to reach out aggressively to the school system to help educate our youth on the story of Thompson have been well received. Jane Johnson organized a series of in-class talks on Dr. Paine as well as the scheduling of numerous tours for schoolchildren to visit the notable historic sites of Thompson. Another milestone in the Society’s history was the hiring of our first Society Administrator, Blair Cole, to manage the building maintenance, docent schedules, website work, volunteer activities and numerous other functions necessary to the operation of the growing group, with members from all over the country. This administrator role will ensure that we are continually pushing ahead with our mission, while not taxing our volunteers excessively. Our quarterly newsletter has been well received and continues our goal of community outreach, tying together all of us with new information on old Thompson.