It includes more than 600 historic structures, most built between the late 17th and early 20th centuries, reflecting the town's growth and history during that time.

The town of Guilford was settled by Englishmen of the Connecticut Colony in 1639, after purchasing the land from Native Americans.

It experienced a brief shipbuilding boom in the late 18th and early 19th century, but saw relatively little industrial activity, and is now a largely suburban residential community.

The town green, whose shape is virtually unaltered since it was laid out in 1639, is lined with commercial, civic, and religious buildings that span the centuries in age.

The town hall is on the east side of the common; it was built in the late 19th century, but was much altered in the 1940s, and no longer carries its historical Romanesque features.