Idaho (ⁱ/ˈaɪdəhoʊ/) is a state in the Rocky Mountain area of the United States. Idaho is the 14th most expansive, the 39th most populous, and the 7th least densely populated of the 50 United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state.