Delaware earned its nickname—The First State—by being first to ratify the U.S. Constitution in 1787. The rest of the states joined the union over the span of 172 years. Alaska and Hawaii were last, joining months apart in 1959. California was purchased from Mexico in 1847 and administered by a federal military authority before it became a state in 1850. Alaska was purchased from Russia in 1867 at less than 2 cents per acre. Wannabe states were required to create their own constitution and ratify the U.S. Constitution before they could seek statehood from Congress.
Source: Admission of States to the Union: A Historical Reference Guide