About: List of counties in Maine

This is a list of the 16 counties in the U.S. state of Maine. Before statehood, Maine was officially part of the state of Massachusetts and was called the District of Maine. Maine was granted statehood on March 15, 1820, as part of the Missouri Compromise. 9 of the 16 counties had their borders defined while Maine was still part of Massachusetts, and hence are older than the state itself. Even after 1820, the exact location of the northern border of Maine was disputed with Britain, until the question was settled and the northern counties signed their final official form, the Webster–Ashburton Treaty, signed in 1842. Almost all of Aroostook County was disputed land until the treaty was signed.