Maine is admitted as the twenty-third U.S. state.

Maine is a state in the New England region of the United States, and the northeasternmost state in the Contiguous United States. It borders New Hampshire to the west, the Gulf of Maine to the southeast, and the Canadian provinces of New Brunswick and Quebec to the northeast and northwest, and shares a maritime border with Nova Scotia. Maine is the largest state in New England by total area, almost as large as the combined area of the remaining five states. Of the 50 U.S. states, it is the 12th-smallest by area, the 9th-least populous, the 13th-least densely populated, and the most rural. Maine's capital is Augusta, and its most populous city is Portland, with a total population of 68,408, as of the 2020 census.

In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sovereignty with the federal government. Due to this shared sovereignty, Americans are citizens both of the federal republic and of the state in which they reside. State citizenship and residency are flexible, and no government approval is required to move between states, except for persons restricted by certain types of court orders.

March 15 is the 74th day of the year in the Gregorian calendar; 291 days remain until the end of the year.