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 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.