Colorado Territory in the context of "Colorado Organic Act"

The Pacific Slope describes geographic regions in North American, Central American, and South American countries that are west of the continental divide and slope down to the Pacific Ocean. In North America, the Rocky Mountains mark the eastern border of the Pacific Slope. In Central and South America, the region is much narrower, confined by the Sierra Madre Occidental in Central America, and by the Andes in South America. The phrase is still used today mostly for scientific purposes to refer to regions inhabited by specific species.

It was and is still occasionally used to describe the region in North America during the 19th century and the expansion of the Old West. It includes the states and territories west of the continental divide that runs down the Rocky Mountains in North America. This included the territories and the states that emerged from them, including California, Oregon Territory, Washington Territory, Nevada Territory, Idaho Territory, Colorado Territory, and Utah Territory. The region is drained by the Columbia, Sacramento, San Joaquin and Colorado River systems. In the United States, the Pacific-slope flycatcher takes its name from the region it inhabits.

The Pike's Peak gold rush (later known as the Colorado gold rush) was the boom in gold prospecting and mining in the Pike's Peak Country of western Kansas Territory and southwestern Nebraska Territory of the United States that began in July 1858 and lasted until roughly the creation of the Colorado Territory on February 28, 1861. An estimated 100,000 gold seekers took part in one of the greatest gold rushes in North American history.

The participants in the gold rush were known as "Fifty-Niners" after 1859, the peak year of the rush and often used the motto Pike's Peak or Bust! In fact, the location of the Pike's Peak gold rush was centered 85 miles (137 km) north of Pikes Peak. The name Pike's Peak gold rush was used mainly because of how well known and important Pike's Peak was at the time. The rush created a few towns such as Denver and Boulder that would develop into cities.