The Wellesley Historical Society was founded in 1925 and incorporated in 1965. Until 1975 it resided in a number of locations, including the Town Hall and the Wellesley Hills Branch Library. In 1975 the Dadmun-McNamara House was purchased from the McNamara family for $1 and moved to its current location at 229 Washington Street. The house had been built in 1824 by Daniel Dadmun, one of the early tollkeepers on the Worcester Turnpike.
The mission of the Society is to serve as the historical resource center for the town of Wellesley; to provide educational programs; to collect, interpret, and display materials pertaining to the history of the town and its people; to inspire public involvement in and appreciation of its heritage and culture.
The Society is a nonprofit 501(c)(3) organization funded entirely by membership dues, the annual appeal, fundraising events, and grants. The Society receives no funds from the tax rolls of Wellesley or the state.