As Maine entered the 18th century, only a half dozen European settlements had survived. Patriot and Loyalist forces contended for Maine’s territory during the American Revolution and the War of 1812. Maine was part of the Commonwealth of Massachusetts until 1820 when it voted to secede from Massachusetts. On March 15, 1820, it was admitted to the Union as the 23rd state under the Missouri Compromise. Maine is the 39th most extensive and the 41st most populous of the 50 United States. This page may not include all the maps we carry for the state of Maine but these are some of the more popular maps. Please click here to search for the city or region that’s most important to you.