Brothers Josiah, Thomas, and Jedediah Dewey joined with Joseph Whiting to establish the first successful mill for both sawing and grinding in Westfield. The mill was located at Two Mile Brook, in what is now the Little River District of Westfield. With the beginnings of that mill operation, the town had given the Dewey brothers grants of land.

In 1715, Jedediah Dewey conveyed to his son Joseph, a tract of about 30 acres "near unto a field commonly called the 'Squawfield'" and bounded on the north "by the foot of the pine hill". This parcel includes the property owned by the Historical Society and extended to the east beyond the present Dewey Avenue.

Around 1735, they cut down trees, made boards and built a four-room house with a kitchen, parlor, and 2 bedrooms. The Dewey’s had 12 children, so they soon outgrew this four-room house and added a new kitchen, a small bedroom, and a buttery at the back of the house. This changed the roof to a salt box style. Later they added three rooms upstairs and changed the roof again.

In 1756, Joseph sold to his son, Joseph Dewey Jr., the same tract of land now expanded to 50 acres with a dwelling house and barn standing on it. It is believed that this dwelling is the front part of the Historical Society house. No exact construction date can be determined, but it seems clear that it was built by Joseph Dewey between the dates of 1717 and 1756. So it has been labelled as "circa 1735". Evidence supports that Dewey may have lived in a "cellar house" dug into the bank at the foot of the pine hill while he was constructing the house from timber cut in the nearby woodlands.

Inevitably there have been many structural changes made to the old house. Probably the most notable change occurred in the early 1800s when the colonial design was converted to a Federal style of architecture which was done in...

Upon receipt of the building from Thomas Conlon, the Board of Trustees set about re-establishing the house’s original color, space and furnishings.