This remained the focus of civic and commercial activity until the Housatonic Railroad opened in 1840.

The area between the green and the railroad then developed as a commercial hub, as the town grew to become a major service center for surrounding communities.

Prominent features include one of the state's longest town greens, which is lined mainly by civic and residential buildings, and the cluster of commercial brick and stone buildings along Bank and Main Streets near the southern end of the green.

Residential areas with fine 19th-century Victorian houses fringe the district, on South Main, East, and Bennitt Streets.

Separately listed buildings on the National Register that are in the district include the United Bank Building and the E. A. Wildman & Co. Tobacco Warehouse; the district excludes the separately listed railroad station.