The state was named for the Colorado River, which Spanish travelers named the Río Colorado for the ruddy (Spanish: colorado) silt the river carried from the mountains. The Territory of Colorado was organized on February 28, 1861, and on August 1, 1876, U.S. President Ulysses S. Grant signed Proclamation 230 admitting Colorado to the Union as the 38th state. Colorado is nicknamed the "Centennial State" because it became a state a century after the signing of the United States Declaration of Independence.
Although today the state's largest population center is around Chicago in the northeastern part of the state, the state's European population grew first in the west, with French Canadians who settled along the Mississippi River, and gave the area the name Illinois. After the American Revolutionary War established the United States, American settlers began arriving from Kentucky in the 1780s via the Ohio River, and the population grew from south to north. In 1818, Illinois achieved statehood. After construction of the Erie Canal increased traffic and trade through the Great Lakes, Chicago was founded in the 1830s on the banks of the Chicago River, at one of the few natural harbors on southern Lake Michigan.John Deere's invention of the self-scouring steel plow turned Illinois's rich prairie into some of the world's most productive and valuable farmland, attracting immigrant farmers from Germany and Sweden. The Illinois and Michigan Canal (1848) made transportation between the Great Lakes and the Mississippi River valley faster and cheaper. New railroads carried immigrants to new homes, as well as being used to ship commodity crops to Eastern markets. The state became a transportation hub for the nation.