The Province of Massachusetts Bay was a colony in New England which became one of the thirteen original states of the United States. It was chartered on October 7, 1691, by William III and Mary II, the joint monarchs of the kingdoms of England, Scotland, and Ireland, and was based in the merging of several earlier British colonies in New England. The charter took effect on May 14, 1692, and included the Massachusetts Bay Colony, the Plymouth Colony, the Province of Maine, Martha's Vineyard, Nantucket, Nova Scotia, and New Brunswick; the Commonwealth of Massachusetts is the direct successor. Maine has been a separate state since 1820, and Nova Scotia and New Brunswick are now Canadian provinces, having been part of the colony only until 1697.

The Thirteen Colonies were a group of British colonies on the Atlantic coast of North America during the 17th and 18th centuries. Grievances against the imperial government led the 13 colonies to begin uniting in 1774, and expelling British officials by 1775. Assembled at the Second Continental Congress in Philadelphia, they appointed George Washington as commander-in-chief of the Continental Army to fight the American Revolutionary War. In 1776, Congress adopted the Declaration of Independence as the United States of America. Defeating British armies with French help, the Thirteen Colonies gained sovereignty with the Treaty of Paris in 1783.