A large rectangular open space in front of Dorchester's riverside lots was set aside as the market square or green. A common feature of New England villages, the green was incorporated into the design of Dorchester by its Massachusetts settlers. They most likely envisioned using this public space for a variety of public uses, mainly as a site for the sale of produce and livestock raised on their farms.
A law passed in 1723 probably brought additional activity to Dorchester's market square. Recognizing that Dorchester was still a frontier village at that time, the law established markets and fairs for the village "for the better encouraging the settling of the town." The markets would be held every Tuesday and Saturday. Then people could buy and sell produce, cattle, and merchandise "at the publick market place already assigned and appointed for that purpose" between sunrise and sunset.
Fairs would be held twice a year, in April and October, and last four days. "All sorts of cattle, horses, mares, colts, grain, victuals, provision and other necessaries, together with all sorts of merchandizes, of what nature soever" were to be sold at the fairs, following the customs of similar fairs that had been held in England for centuries.
Sales of human property also took place in the market square. Slaves, often advertised for their particular skills, were frequently offered for sale along with other possessions such as livestock, tools, and furniture.
Because of all the activity that took place on the green, nearby town lots were probably considered very valuable as potential business sites. When a merchant advertised the sale of a lot facing the market in 1747, he took special care to note that the site with its house and stores would be "convenient for a Store-Keeper." Eight years later William Power advertised his intention to open a store and tavern on Dorchester green.
The market square might have been the site where local militia units assembled and drilled. A part-time military force of able-bodied citizens armed and equipped at their own expense, the militia was expected to supplement regular armed forces in emergencies. When the "Gentlemen belonging to St. George's Troop" were called in 1748 to meet "at the usual Place of Parade in Dorchester," it is possible that they assembled on the green. During the Revolutionary War troops might have bivouacked on the green.
After the war, as Dorchester was gradually abandoned, this once-open public space was gradually overgrown and its many uses forgotten. Once again maintained as an open space, the green gives visitors to Colonial Dorchester State Historic Site a sense of the many public functions of the village.