By the close of the 19th century, railroads and telegraph lines spanned the American continent. Settlement had spread to such an extent throughout the West that the Census of 1890 announced there was no longer a frontier line. Without the “frontier beyond,” Americans began to view the wilderness differently. It was not, after all, endless and inexhaustible, but finite, shrinking and worthy of protection. The most effective spokesman for the cause of western wilderness preservation in the latter decades of the 19th century was the Scottish-born naturalist, John Muir (1838-1914). After studying at the University of Wisconsin, Muir hiked all over the West, studying and writing about the region’s wild places, especially its mountains, forests and glaciers. In arguing for the preservation of nature in its primeval state, Muir was echoing views expressed earlier by Thoreau and Emerson, but he articulated them with new intensity. Muir was particularly entranced by the beauty of California’s Yosemite Valley and its surrounding Sierra Neva mountains, which he called the “range of light.” At his urging, the area was finally designated a national park in 1890, the nation’s third after Sequoia (1890) and Yellowstone (1872). In 1892, Muir founded the Sierra Club, an organization dedicated to the preservation and enjoyment of the wilderness.

The idea of a transcontinental railroad attracted increasing public enthusiasm after the California gold rush of 1849. But sectional rivalries prevented any action until 1862, when Congress made lavish land grants to two railroad companies, the Union Pacific and the Central Pacific, to enable them respectively to build westward across the Great Plains from Omaha, and eastward over the Rockies from Sacramento. The Act was a tremendous spur to construction, but there were daunting logistical problems to be overcome. Everything required — ties, stone, rails, rolling-stock, machinery — had to be hauled over long distances. Equally serious was the shortage of labor. Union Pacific construction crews consisted chiefly of Irish immigrants, who sometimes had to exchange their picks for rifles in order to fight off Indian attacks. The Central Pacific relied mainly on imported Chinese laborers who had to blast tunnels through the High Sierras using recently developed nitro-glycerine, which killed many of them. Tracklaying in rugged terrain and extremes of weather averaged only 2-1/2 miles a day, but on May 10, 1869 the two lines met at Promontory Point, Utah, where a final symbolic golden spike was driven into place. Both tracks had soon to be extensively reconstructed, but the completion of the first transcontinental railroad was a remarkable feat, news of which triggered celebrations across the nation.

The acquisition of Oregon and discovery of gold in California in the 1840s created a need for a transportation network linking the East with the Pacific coast. California pressure for a regular stagecoach service led in 1857 to the award of a federal mail contract to a syndicate headed by John Butterfield, the owner of stagecoach lines in New York. The following year, Butterfield’s Overland Mail Company began a semi-weekly mail service, operating in each direction on a 25-day schedule over a 2,800 mile route between St. Louis and San Francisco. Thousands of miles of overland routes were established in the next decade. Best-known was the Pony Express, established in 1860 by the firm of Russell, Majors and Waddell. Relays of pony riders covered the 1,966 miles between St. Joseph, Missouri and Sacramento, California in only ten days, thus demonstrating the superiority of the Central Plains route over the more circuitous southerly route followed by Butterfield. But without a government subsidy the Pony Express was incapable of make a profit. In any case it was rendered obsolete after only eight months by the completion of the transcontinental telegraph line. When Russell, Majors and Waddell went bankrupt in 1862, its remaining freight lines were bought by Ben Holladay, who, after organizing a thriving stagecoach empire spanning most the the West, sold out in 1866 to Wells, Fargo, and Co.

The California gold rush stimulated prospecting throughout the western mountains, producing a succession of strikes. In 1858, gold was discovered near Pike’s Peak in Colorado. The next year, Nevada yielded an even richer prize — the Comstock Lode, the greatest single deposit of precious metals ever found in the U.S. The leading mining camp there, Virginia City, grew rapidly into the thriving metropolis immortalized in Mark Twain’s Roughing It, boasting an opera house, theatre, newspapers, stock exchange, saloons, dancehalls and gambling-houses. After the shallower deposits were exhausted, and the simple and inexpensive placer-mining techniques used by most miners rendered useless, California capitalists bought up the prospectors’ claims and installed deep-level quartz-mining machinery. In 1873, these “Silver Kings” struck the “Big Bonanza” 1,100 feet down. In 1874, gold was discovered on Sioux lands in the Black Hills of Dakota Territory. Nearly overnight the ramshackle town of Deadwood became home to 15,000 miners. Mining towns also sprung up in Leadville (1877-silver), Cripple Creek (1891-gold), and Telluride, Colorado (1875-gold); Tombstone, Arizona (1877-silver); Couer d’Alene, Idaho (1833-gold); Butte, Montana (1882-copper); and elsewhere. Many towns survived after the mines ran out, but others became ghost towns.

Gold-rush California was a crude, boisterous and often violent place. Its non-Indian population was overwhelmingly young and male — women made up only one-twelfth of the population in 1850 — and it included a greater variety of ethnic and racial groups than anywhere in the nation. As well as Americans, Irishmen, Frenchmen, Germans and Mexicans there were many thousands of Chinese who soon became victims of popular animosity and physical intimidation. The California Indians (perjoratively called “Diggers”) were treated even worse; many were massacred or forced into legal slavery. Though the California mines yielded about $200 million in the five years of the gold rush, only a handful of fortune seekers struck it rich and many of the disappointed took solace in drink and gambling. In the roaring mining camps, given such names as Poker Flat, hell’s Delight and Dry Diggings, and in boomtowns like San Francisco and Sacramento, rooms rented for $1,000 a month, eggs cost $10 a dozen, and normal social restraints ceased to operate. The miners included many desperadoes and adventurers, and crime became endemic. With the military authorities impotent, law-abiding elements set up vigilance committees to protect life and property. But miscarriages of justice were common and order was restored only some years after California became a state in 1850.

On January 24, 1848, a few days before the signing of the peace treaty whereby Mexico ceded California to the U.S, gold was discovered on the Sacramento Valley estate of the Swiss-born frontiersman, John Augustus Sutter. Despite his attempts to keep it secret, the news leaked out and from all over California men flocked to the diggings. By September the news had reached the East and the whole country succumbed to golf fever. Clerks deserted their desks, soldiers their regiments, husbands their families. Within a year some 80,000 “Forty Niners” had poured into California from all over the world, most of them intent on sudden wealth. Many traveled overland by covered wagon, following the trails across the Plains and mountains, at least 5,000 dying from cholera, starvation, exhaustion and Indian attack. Thousands of others chartered vessels around Cape Horn, a voyage of 18,000 miles occupying four to eight months. Still others sought a short cut to the Pacific through the sweltering jungles of the Panama isthmus. It was one of the largest mass migrations in history which, in two years, transformed the sleepy seaside settlement of San Francisco (1847 population approximately 600) into a major seaport and the financial and cultural center of West (1850 population approximately 25,000).

Whichever route the emigrants chose, they found the journey across the continent slow, fatiguing and full of hardship. Averaging only about 10 or 15 miles a day — enduring heat, dust, wind, sand, mud and sometimes snow — the pioneers rarely reached their destination in less than three months. Accidents, sickness and death took a regular toll as was evident from the emigrant graves, bones of oxen, discarded household goods and broken wagons that littered the overland trails. One of the worst disasters befell the California-bound Donner party in 1846. Poorly equipped and ill-advised, they became trapped by snows in the Sierra Nevada mountains. Many died of starvation and the survivors resorted to cannibalism before they were finally rescued.

Yet despite the difficulty and hardship, the emigrants kept coming, motivated by many things. For the Mormons; it was to escape religious persecution and build a “community of Saints” in the great Salt Lake Valley. For others, it was to farm the fertile valleys of California and Oregon or strike it rich in fields of gold. Some came for freedom and adventure or to escape the past. But in one way or another they all came for the same thing — the promise of a better life.

The Mexican War of 1846-1848 broke out ostensibly over a dispute about the Texan boundary. But it really originated in the expansionist spirit of “manifest destiny,” of which President James K. Polk was a leading proponent. Polk came to office determined to acquire the Mexican provinces of California and New Mexico and when Mexico refused to sell them, used a border clash as a pretext for war. Although American opinion was deeply divided over the conflict, the war turned out to be a succession of triumphs for American arms. The two provinces Polk coveted were easily overrun: General Zachary Taylor overwhelmed a much larger Mexican army at Buena Vista (February 1847); and General Winfield Scott’s seaborne expedition to Vera Cruz fought its way into the heart of Mexico against superior forces and captured Mexico City (September 1847), forcing Mexico to make peace. By the Treaty of Guadalupe-Hidalgo (February 1848), Mexico ceded the territories of California and New Mexico and acknowledged the Rio Grande as the Texas boundary. While the war brought the U.S. vast territorial gains — extending America’s western boundary to the Pacific — it also revived the simmering conflict over slavery and its extension to new territories.