Colorado

The Centennial State

Colorado was carved out of the Kansas, Nebraska, Utah and New Mexico territories after gold was found near present-day Denver in 1858. The “Pikes Peak or Bust” rush brought tens of thousands of prospectors, and in 1861 Congress created the Colorado Territory. Statehood took longer. Congress passed an enabling act in 1875, Colorado voters approved a state constitution on July 1, 1876, by about 15,400 votes to 4,100, and on August 1, 1876, President Ulysses S. Grant proclaimed Colorado the 38th state. Because that was the hundredth anniversary year of the Declaration of Independence, Colorado has been known ever since as the Centennial State, though the nickname has never been made official.

A river’s name

Colorado is a Spanish word meaning “colored red.” Spanish explorers used it for the Colorado River, whose muddy water runs reddish through the canyons of Utah and Arizona. When Congress created the territory in 1861, the House bill actually called it Idaho, and Jefferson and Arcadia were also suggested. The Senate swapped in Colorado, reasoning that the great river rose in the territory’s mountains. There was a catch: the upper part of the river, inside Colorado, was then called the Grand River. Only in 1921, at Colorado’s urging, did Congress rename it the Colorado.

Denver and the mile-high step

Denver became the territorial capital in 1867, after brief stints in Colorado City and Golden, and a statewide vote in 1881 made it the permanent capital over Pueblo, Colorado Springs, Cañon City and Salida. The gold-domed Capitol, built of Colorado granite, is famous for a step on its west side engraved “One Mile Above Sea Level.” Later surveys found the true mile-high point on other steps, and there are now three markers. The capital page tells the story.

High country

Colorado has the highest average elevation of any state, and the Rocky Mountains run through its center. Many of its symbols come from that high country: the Rocky Mountain columbine, the state flower since 1899; the Colorado blue spruce, chosen by schoolchildren in 1892; the bighorn sheep, the state animal; and aquamarine, mined at around 14,000 feet on Mount Antero. Skiing and snowboarding are the official state winter sport, and pack burro racing, a race run beside a burro carrying a miner’s pack, is the official summer heritage sport.

The eastern third of the state is high plains, and its symbols are different. The state bird is the lark bunting, a prairie bird whose males are black with bold white wing patches, and the state grass is blue grama, which holds the prairie soil in place.

Symbols chosen by students

Colorado has 26 official symbols, and an unusual number came from young people. A fourth-grade class campaigned for two years for Stegosaurus, which Governor Richard Lamm made the state fossil by executive order in 1982. Other fourth graders proposed the western painted turtle as the state reptile in 2008. Students also pushed for the western tiger salamander, the state’s shelter pets and the winter sport, and Girl Scouts led the campaigns for Yule marble, the state rock, and the claret cup cactus. The state rock has a famous résumé: Yule marble from Gunnison County was used for the Lincoln Memorial and the Tomb of the Unknown Soldier. See every symbol on the Colorado symbols page.

The flag, with its red C around a gold disk, is one of the most recognizable state flags. The motto, Nil sine numine, Latin for “Nothing without Providence,” has been on the seal since territorial days.

Land and people

Colorado covers 104,094 square miles, the eighth largest state, and had about 6.01 million residents in 2025, 20th in the country. It borders Wyoming, Nebraska, Kansas, Oklahoma, New Mexico and Utah, and touches Arizona at the Four Corners. Most Coloradans live along the Front Range, where the plains meet the mountains: Denver, with about 741,000 people, is the largest city, followed by Colorado Springs, Aurora and Fort Collins.