Colorado, a state of the American Union, in 37°—41° N. lat., and 102°—109° W. long., traversed from north to south by ranges of the Rocky Mountains. It takes its name from the river Colorado, to the basin of which all the western slope of the state belongs—as the eastern to the Mississippi valley—while part of the south is drained by the Rio Grande and its head-streams. The area is 103,645 sq. m., or rather more than half the extent of France; so that Colorado ranks as fifth in area among the states, being surpassed in this regard by Texas, California, Nevada, and Montana. The vast ranges which traverse this region have mostly an approximate north and south direction, with many deviations. The high plains and over-drained mesas to the west are not clearly marked off from the mountain-region; and much of the western slope is actually mountainous. The eastern slope, which embraces about two-fifths of the whole state, is, apart from the foot-hills skirting the flank of the mountain-region, an open and comparatively treeless plain, with a surface singularly monotonous, and for the most part devoted to the pasturage of cattle and sheep, an interest which is of high importance in nearly all parts of Colorado. This level region averages 5000 feet in altitude, and its lowest point is 3000 feet above sea-level. The mountain-region contains many peaks exceeding 14,000 feet in height, the loftiest being Blanca
Peak (14,464 feet); while the summits exceeding 13,000 feet are stated to be more than one hundred in number. The mountains, notwithstanding their general parallelism, are greatly broken into short and variously named chains, there being no one ridge that can distinctly claim to rank everywhere as the main range of the system. Six passes cross mountain-ranges at points over 12,000 feet high; the Argentine Pass is 13,000 feet in altitude. Railways are led across many of these passes, and their construction through the valleys and cañons has called for many brilliant displays of engineering skill and boldness. A marked feature of the mountain-region is presented in the parks, or rich mountain-valleys, often very spacious, and generally bearing evidence of being the basins of lakes once extensive, but now nearly or quite dried up. The central mountain-region, with its parks, cañons, and hot springs, and its rich mineral deposits, has attracted most attention. The western part of the state is far less accessible and less developed, although its mineral wealth and the construction of railways have led to the settlement of some parts of the region.
The rainfall of Colorado is small; yet the great altitude causes a considerable local fall of rain and snow, and several important streams take their rise in the state, including several tributaries of the Colorado; the Arkansas and South-Platte, flowing to the Mississippi; and the Rio Grande, the only stream which reaches the sea under its own name. Extensive and important irrigation-works are fed by some of these streams. Colorado has a great reputation as a health-resort, especially for persons with pulmonary disease. The dryness of the air is the great factor in the recovery of consumptive patients in this region; but some invalids only after a considerable period become so habituated to the rarefaction of the atmosphere as not to be seriously annoyed by it. The medicinal and thermal springs of the state are numerous, and are visited by large numbers. A peculiar disease called 'mountain fever' is endemic in some places, attacking principally strangers from lower levels of country.
Wheat, maize, barley, oats, hay, potatoes, fruits, and garden and dairy products are the staples of agriculture, which is remunerative in all sections where irrigation can be effected. In 1900 Colorado had 16,000 miles of irrigating canals and ditches, supplying an area of over 3,500,000 acres with water, without counting ditches made by private persons. Visitations of insect-plagues, including the well-known Colorado potato-beetle, have hitherto proved very destructive in this state; but the Rocky-mountain locust (see LOCUST), formerly a terrible enemy to the farmers, has of late years been comparatively harmless. Cattle and sheep raising are important industries; the stock in 1897 was valued at over $17,000,000. Lumber-cutting also employs a number of hands.
The discovery of gold (1858) in the neighbourhood of Pike's Peak led to the first important settlements of English-speaking people in this region. The earliest discoveries were of placer-deposits; but quartz-mining soon followed, and although many of the quartz-lodes yield a highly sulphuretted material, the introduction of improved methods of treatment has finally rendered these ores, so refractory under the old processes, highly important as a source of gold. In more recent years a considerable proportion of gold has been afforded by the richly argentiferous lead-carbonate ores, for which the state is famous. From 1873 on the silver production exceeded that of gold in importance; and the state ranked as the first in the United States in out-turn of silver, second or third in its gold, and first or second in the production of the precious metals in general. In the working of the best silver ores much lead is obtained, and Colorado takes rank as the first state in lead-production. Vast sums of money have been invested in the construction of works for hoisting and reducing the ores; and railways have been built along the mountain-cañons, generally at a very high cost, so as to make the mines accessible. Mining and smelting operations have been much facilitated by the discovery of large beds of coal, usually of good quality, though classed as a lignite. Of late the gold produce (24,000,000 in 1898) again exceeds the silver (14,250,000); and the state remains the foremost in the Union as a producer of the two precious metals. Iron and Bessemer steel rails are among the manufactures of the state; copper, cement, fireclay, and manganese are wrought to a greater or less extent; and there are thirty petroleum wells near Florence.
History.—Not quite one-half of this region was acquired by the United States from France in the Louisiana purchase of 1804; the remainder was ceded by Mexico under the treaty of 1848, together with California and New Mexico, of which last it formed a portion. The southern part of Colorado has for many years had a small Spanish-speaking population, partially of Indian descent. Colorado was organised as a territory in 1861, and was admitted as a state in 1876. The population is of mixed origin, but is largely derived from the older states of the Union. The distinctly American traits of enterprise and progress, shown alike in business methods and in measures for the spread of popular education, are nowhere more conspicuous than here. The principal towns are Denver, the capital (pop. 106,713), and Pueblo (24,558). There are also a number of minor towns, most of them mining centres; but the fall in the value of silver, and the closing of many of the mines (since 1893), has unfavourably affected not a few of them. Pop. of Colorado (1860) 34,277; (1870) 39,864; (1880) 194,327; (1885) 243,910; (1890) 412,198.