From approximately A.D.1 to 1299 A.D. the prehistoric cliff dwellers (Anasazi) lived in southwestern Colorado. Besides the Anasazi, many Native American groups have lived in Colorado. The Utes lived in the mountains, the Cheyenne and Arapahoe resided on the plains from the Arkansas to the Platte rivers, and the Kiowas and Comanches lived south of the Arkansas River. The Pawnee tribe hunted buffalo along the Republican River and the Sioux sometimes hunted on the outskirts of the Cheyenne and Arapahoe lands.

Through the Louisiana Purchase in 1803, the United States acquired a vast area which included what is now most of eastern Colorado. By the Treaty of Hidalgo in 1848, Mexico ceded to the United States most of that part of Colorado not acquired by the Louisiana Purchase. In 1850, the Federal Government purchased Texas' claims in Colorado, and the present boundaries of Colorado were established.

The earliest permanent European settlements were planted in the San Luis Valley. San Luis, on the Culebra River, was settled in 1851, followed in the next few years by San Pedro, San Acacio, and Guadalupe.

William Green Russell discovered a small placer gold deposit near the confluence of the South Platte River and Cherry Creek in 1858 that spurred the gold rush in Colorado. The State's gold and silver mining boom days are well known. Mrs. J. Brown, socialite wife of a Colorado mining tycoon was immortalized in the Broadway Musical, "The Unsinkable Molly Brown," so called after she survived the sinking of the ocean liner "Titanic". Her home in Denver has been maintained as a museum.

Soon after gold was discovered near Denver, the region around Pike's Peak became the Colorado Territory. Other names, such as Colona, Jefferson, Osage and even Idaho, were suggested and discarded in favor of Colorado, Spanish for "red" in reference to the color of the water of the Colorado River.

St. Charles (renamed Denver City), and its rival, Auraria, were settled on the east and west sides of Cherry Creek (now lower downtown Denver) in 1858. Soon after these towns were established, Boulder City near the mouth of Boulder Canyon was founded. To the north, on the Cache La Poudre River, a fur trader, named Antoine Janise, began a settlement called Colona that later changed its name to La Porte. Arapahoe City and Golden Gate were established to the west of St. Charles and Auraria in the closing days of 1858, while to the south, at the mouth of Fountain Creek, the town of Fountain City (later to be named Pueblo) was laid out. Another site, El Paso, was staked out near Pike's Peak.Colorado was originally part of the Nebraska, Utah, Kansas, and New Mexico Territories. In 1859 a provisional territorial government was formed, called the Territory of Jefferson. In 1861 Congress created the Territory of Colorado. On August 1, 1876, President Ulysses S. Grant issued the proclamation of statehood. Colorado was the 38th state to join the Union.