An animated map showing the incorporation of towns in Southern New England over time.

Plymouth, MA was established in 1620 by the pilgrims on the Mayflower, kicking off the British colonization and settlement of New England. After the Massachusetts Bay area, colonists began settling along the coastline and the Connecticut River Valley, eventually moving further into the hills. By the time the US Constitution was ratified, the “frontier” had moved beyond Southern New England. Throughout the 19th century, the “blank spaces” on the map began filling in as these areas were incorporated as towns, and some larger towns split into smaller towns.

Present-day town boundaries haven’t changed much since the beginning of the 20th century, and this region has no unincorporated areas.

Prior to the Mayflower landing in Plymouth, this region had been visited by French, Dutch, and British traders. The Nipmuc, Pequot, Mattabesic, Narragansett, Massachusett, Wampanoag, and other native peoples had lived in this area prior to European settlement. The Native Americans were almost completely driven out of Southern New England by war, disease, exploitation.

This map displays towns by the year they were incorporated as municipalities. Some towns re-incorporated as cities later on. In Southern New England, the basic municipal entity is a town or city. While these states are divided into counties, county government is weak or non-existent.

Note: “Boroughs” and “villages” that are incorporated within towns are not displayed on this map. The four Massachusetts towns that were disincorporated in 1938 when the Quabbin reservoir was created are not displayed on this map.

Wikipedia has pages listing towns in Connecticut, Massachusetts, and Rhode Island, along with their year of incorporation and other information. This collection and organization of this information by Wikipedia editors saved me a lot of time when making this map.