Patriots' Day is not a federal holiday. It is an official state holiday in Maine, legally recognized by the state government but not by the United States federal government. This distinction means its observance is mandated at the state level rather than the national one.
Federal holidays are designated by the U.S. Congress and apply to federal employees and institutions across all 50 states. State holidays, in contrast, are established by individual state legislatures and are only officially observed within that state's jurisdiction. Maine, along with Massachusetts, observes Patriots' Day on the third Monday in April to commemorate the Battles of Lexington and Concord, the first engagements of the American Revolutionary War. Connecticut and Wisconsin also give some form of official recognition to the day.
The practical implication of this status is that on Patriots' Day in Maine, state and local government offices, public schools, and many private businesses are closed. However, federal institutions located within the state, such as post offices and federal courts, remain open and operational as they adhere strictly to the federal holiday calendar.