The north to south ranges of the Rocky Mountains, with more than 50 peaks over 14,000 feet, traverse the western half. Their crests form the Continental Divide. The rest of the state is covered by the western portion of the Great Plains, grazing and farming land. Major rivers rise in the state-the Colorado, Rio Grande, Arkansas, North Platte, and South Platte.
Colorado's economy has been dominated successively by mining, agriculture, and manufacturing. Huge reserves of petroleum, natural gas, and coal remain.
Irrigation made possible the varied agriculture of the plains. Food processing is the state's leading industry.
Manufacture of ordnance and other military material in government plants is important. The facilities for year round recreation make tourism a major aspect of the economy.
More than 75% of the population resides in urban areas in a strip north and south of Denver in the center of the state. Less than 5% were born outside the United States, but only approx. 50% were born in Colorado.
The United States acquired the eastern part of Colorado from France by the Louisiana Purchase of 1803. The remainder was ceded by Mexico in 1848 after the Mexican War. Discovery of gold and silver spurred immigration from other states, and Colorado became a territory in 1861. Building of railroads after 1870 expanded the population rapidly. WWI stimulated agriculture, and WWII shifted the economic emphasis to manufacturing.