However, from the perspective of Massachusetts law, politics, and geography, cities and towns are the same type of municipal unit, differing primarily in their form of government and some state laws which set different rules for each type.

For example, Dorchester was incorporated in 1630 and originally included all of the current Dorchester, now the largest neighborhood of Boston, plus the Boston neighborhood of Mattapan, and all of present-day Quincy, Milton, Braintree, Randolph, Holbrook, Canton, Sharon, Stoughton, Avon and the northeast portion of Foxboro.

Some towns and cities were annexed to others; disincorporated; or ceded to another state in their entirety.

This list does not include territory changes affecting only part of a municipality; see History of Massachusetts.

The following towns were ceded to the Rhode Island colony in 1747 as part of a border dispute: Due to a 1642 surveying error and long-running political disputes, the following Massachusetts towns joined the Connecticut Colony in late 1749: All settlements in the District of Maine were ceded when the State of Maine gained its independence from Massachusetts in 1820 as part of the Missouri Compromise: Many municipalities have changed names.