Pike expedition: Lieutenant Zebulon Pike sees a distant mountain peak while near the Colorado foothills of the Rocky Mountains (it is later named Pikes Peak).

The Compromise of 1850 transfers a third of Texas's claimed territory (now parts of Colorado, Kansas, New Mexico, Oklahoma, and Wyoming) to federal control in return for the U.S. federal government assuming $10 million of Texas's pre-annexation debt.

Denver, Colorado is founded.

Colorado is organized as a United States territory.

Colorado is admitted as the 38th U.S. state.

In Colorado, Nicholas Creede strikes it rich in silver during the last great silver boom of the American Old West.

Women in the U.S. state of Colorado are granted the right to vote.

Governor Davis H. Waite orders the Colorado state militia to protect and support the miners engaged in the Cripple Creek miners' strike.

Forty-five men, women, and children die in the Ludlow Massacre during a Colorado coal-miner's strike.

President Dwight D. Eisenhower authorizes the creation of the United States Air Force Academy in Colorado.

A plane carrying the Wichita State University football team, administrators, and supporters crashes in Colorado killing 31 people.

Gay rights: The Supreme Court of the United States rules in ''Romer v. Evans'' against a law that would have prevented any city, town or county in the state of Colorado from taking any legislative, executive, or judicial action to protect the rights of gays and lesbians.