Arizona is the 48th state and last of the contiguous states to be admitted to the Union, achieving statehood on February 14, 1912. Historically part of the territory of Alta California in New Spain, it became part of independent Mexico in 1821. After being defeated in the Mexican–American War, Mexico ceded much of this territory to the United States in 1848. The southernmost portion of the state was acquired in 1853 through the Gadsden Purchase.
North Dakota weathered the Great Recession of the early 21st century with a boom in natural resources, particularly a boom in oil extraction from the Bakken formation, which lies beneath the northwestern part of the state. The development drove strong job and population growth, and low unemployment. However, falling oil prices have put pressure on state finances, leading to questions about the lack of diversity in the North Dakota economy and its vulnerability to commodity price swings.