National North Dakota Day is observed every April 19 to celebrate North Dakota's admission as the 39th state to join the United States. The day was established by National Day Calendar and highlights the state's rich history and culture. North Dakota, named after the Dakota Sioux word meaning "friend" or "ally," is known as the Peace Garden State, referencing the International Peace Garden located on the Canada-U.S. border, which symbolizes peace between the two nations. The state's history includes its exploration by French-Canadian fur traders in the mid-18th century and its transition through various territorial claims before becoming a state in 1889. National North Dakota Day is part of the National State Days project, which celebrates each U.S. state in the order of their statehood, with North Dakota Day specifically commemorating the state's unique heritage.