Milling operations began along the Looking Glass River near this district in 1836, and the first portion of the village of Portland was platted in 1837.

Around the same time, the first building in the district was erected by William R. Churchill at what is now the east corner of Kent and Bridge Streets.

Major fires in 1872 and 1877 destroyed many of the older wooden buildings, and in 1877 the village mandated that further construction within the district be brick.

[2] Portland's population growth slowed after 1880, but the business district slowly grew, extending southwestward down Kent Street to Academy by the late 1910s.

After World War II, more of the commercial buildings in the district were refurbished, and some new construction took place, notably the 1948-49 Sun Theatre at 227 Maple Street.