Cummington was first settled in 1762 and was officially incorporated in 1779. It was named after Colonel John Cummings, the original landholder.
The first Congregational Church minister was Rev. James Briggs (1743 - 1825) of Norton, Massachusetts, and a graduate of Yale College around 1775. Briggs was the son of Deacon James and Damaris (White) Briggs, and the husband of Anna Wiswall.
Although a small town, several Revolutionary War patriots are buried there, including Nathaniel Holbrook, Seth Wilder, Sr., and Seth Wilder, Jr.
Noted poet and newspaper editor William Cullen Bryant was born in Cummington, and returned for many years to summer in the town. His house is now preserved and open to the public as the William Cullen Bryant Homestead. The town hosts the Cummington Fair every August on the town's fairgrounds. The fair features many events including adult and 4-H exhibition halls, a craft barn, vaudeville stage, antique car parade, oxen pull, and an assortment of fair rides, games, and food stands.
The town was the subject of a 1945 documentary film, The Cummington Story, about the welcome given to a group of European refugees.