The territory of Maine has been inhabited by Indigenous populations for about 12,000 years, after the glaciers retreated during the last ice age. At the time of European arrival, several Algonquian-speaking nations governed the area and these nations are now known as the Wabanaki Confederacy. The first European settlement in the area was by the French in 1604 on Saint Croix Island, founded by Pierre Dugua, Sieur de Mons. The first English settlement was the short-lived Popham Colony, established by the Plymouth Company in 1607. A number of English settlements were established along the coast of Maine in the 1620s, although the rugged climate and conflict with the local Indigenous people caused many to fail. As Maine entered the 18th century, only a half dozen European settlements had survived. Loyalist and Patriot forces contended for Maine's territory during the American Revolution. During the War of 1812, the largely undefended eastern region of Maine was occupied by British forces with the goal of annexing it to Canada via the Colony of New Ireland, but returned to the United States following failed British offensives on the northern border, mid-Atlantic and south which produced a peace treaty that restored the pre-war boundaries. Maine was part of the Commonwealth of Massachusetts until 1820 when it voted to secede from Massachusetts to become a separate state. On March 15, 1820, under the Missouri Compromise, Maine was admitted to the Union as the 23rd state.
The territory of Maine has been inhabited by Indigenous populations for about 12,000 years, after the glaciers retreated during the last ice age. At the time of European arrival, several Algonquian-speaking nations governed the area and these nations are now known as the Wabanaki Confederacy. The first European settlement in the area was by the French in 1604 on Saint Croix Island, founded by Pierre Dugua, Sieur de Mons. The first English settlement was the short-lived Popham Colony, established by the Plymouth Company in 1607. A number of English settlements were established along the coast of Maine in the 1620s, although the rugged climate and conflict with the local Indigenous people caused many to fail. As Maine entered the 18th century, only a half dozen European settlements had survived. Loyalist and Patriot forces contended for Maine's territory during the American Revolution. During the War of 1812, the largely undefended eastern region of Maine was occupied by British forces with the goal of annexing it to Canada via the Colony of New Ireland, but returned to the United States following failed British offensives on the northern border, mid-Atlantic and south which produced a peace treaty that restored the pre-war boundaries Maine was part of the Commonwealth of Massachusetts until 1820 when it voted to secede from Massachusetts to become a separate state. On March 15, 1820, under the Missouri Compromise, .Maine was admitted to the Union as the 23rd state.