In 1783, King George III signed the Treaty of Paris, officially ending the American War of Independence and recognizing the 13 former British colonies -- New Hampshire, Massachusetts Bay, Rhode Island, Connecticut, New York, New Jersey, Pennsylvania, Delaware, Maryland, Virginia, North Carolina, South Carolina and Georgia -- as "free sovereign and independent states" [source: National Archives].
As part of the Treaty of Paris, England handed over the area that is now the eastern United States, from the Atlantic Ocean all the way to the Mississippi River, bound by Canada to the north and the Spanish colonies of East and West Florida to the south [source: National Atlas]. This territory far exceeded the original boundaries of the 13 colonies. In an effort to avoid territorial disputes among the new states, Congress convinced the states to relinquish control of uninhabited lands to the Federal government.
These "unappropriated" frontier lands were divided into territories with names like the Northwest Territory, Mississippi Territory and Southwest Territory. One by one, portions of those territories petitioned for statehood, which is how the Northwest Territory eventually became the states of Ohio, Indiana, Michigan, Illinois, Wisconsin and Minnesota.
Other states were carved out of existing states: Vermont was sliced from New York (1791); Kentucky was born from Virginia (1792); Tennessee began as the western extension of North Carolina (1796); Maine was originally part of Massachusetts (1820); and West Virginia split from Virginia in 1863 to join the Union in the Civil War [sources: National Atlas and West Virginia Archives and History].
The rest of the U.S. began as land purchased from other countries or as the spoils of war. The Louisiana Purchase (1803) is the largest and most famous, doubling the size of the nation for a price tag of $15 million [source: Library of Congress]. The U.S. also bought Florida from Spain and Alaska from Russia.
Large portions of the American West were once Mexican territories. Texas won independence from Mexico in 1836 and was annexed by the U.S. as a state in 1845. After losing the Mexican-American War, Mexico ceded the land that would become California, Nevada, Utah, Arizona and parts of Colorado and New Mexico for $15 million [source: National Atlas].
Hawaii, the most geographically isolated state, first became a U.S. territory in 1898, after American colonists overthrew the Hawaiian kingdom in a peaceful coup [source: Hawaii Tourism Authority]. Hawaii didn't become a state until 1959, well after its critical role in triggering America's involvement in World War II.
Puerto Rico isn't the only contender for the 51st state. On the next page, we'll discuss Puerto Rico's chances and look at some of the statehood failures that came before it.