Human beings came to the land now known as Idaho about 15,000 years ago. Until 1805, only Indians and their ancestors had ever lived in the area, eking out a bare living from seeds and roots, insects, small animals, and what fishing and big-game hunting they could manage. At the time of white penetration, Shoshone and Northern Paiute lived in the south, as well as two linked tribal families, the Salishan and Shapwailutan (including the Nez Percé, who greeted the Lewis and Clark expedition when it entered Idaho in 1805; it was their food and canoes that helped these explorers reach the Columbia River and the Pacific).
Fur trappers—notably David Thompson, Andrew Henry, and Donald Mackenzie—followed within a few years. Missionaries came later; Henry Harmon Spalding founded a mission among the Nez Percé in 1836. The Oregon Trail opened in 1842, but for two decades, people merely crossed Idaho over it; virtually no one settled. In 1860, 14 years after Idaho had officially become US land through the Oregon Treaty with the United Kingdom, Mormons from Utah established Franklin, Idaho's first permanent settlement, and began farming. Gold was discovered that summer in northern Idaho; a gold rush, lasting several years, led directly to the organizing of Idaho Territory on 10 July 1863.
Boise became the capital of Idaho in 1864, and the following decade saw the inauguration of telegraph service, the linking of Franklin with the transcontinental railway, and the birth of the territory's first daily newspaper. Idaho's population nearly doubled between 1870 and 1880, and the pressure of white settlement impinging on Indian hunting and fishing grounds touched off a series of wars in the late 1870s. The most famous of those was the Nez Percé War, culminating in Chief Joseph's surrender in Montana on 5 October 1877 and in the subsequent confinement of Idaho Indians to reservations.
Lead and silver were discovered in south-central Idaho in 1880 and in the panhandle in 1884, touching off yet another stampede of would-be miners. With a population of 88,548 in 1890, Idaho was eligible to enter the Union, becoming the 43rd state on 3 July. Statehood came to Idaho at a time of turmoil, when Mormons and non-Mormons were contending for political influence, the Populist Party was challenging the established political organizations, and violent labor disputes were sweeping the mining districts. In 1907, in a case that grew out of the labor conflict, William "Big Bill" Haywood (defended by Clarence Darrow) was acquitted on charges that he conspired to assassinate former Idaho Governor Frank Steunenberg, murdered on 30 December 1905.
From 1895 onward, federal land and irrigation projects fostered rapid economic growth. The modern timber industry began in 1906 with the completion of one of the nation's largest sawmills at Potlatch. By World War I, agriculture was a leading enterprise; however, a farm depression of the 1920s lasted up to the Great Depression of the 1930s and ended only with the onset of World War II. After the war, an agro-industrial base was established, with fertilizers and potato processing leading the way. Idaho has also developed a thriving tourist industry, with large numbers of vacationers visiting the Sun Valley ski resort and the state's other scenic areas. Population expansion and the push for economic growth have collided with a new interest in the environment, creating controversies over land-use planning, mineral development, and water supply and dam construction. In April 2000 the National Wildlife Federation urged President Clinton to designate the Owyhee Canyonlands, a 1.8-million acre scenic area in southwest Idaho, a national monument. The efforts to persuade Clinton failed, and environmentalists, ranchers, and off-road vehicle riders in 2003 were coming together to agree on a conservation plan suitable to all.
Idaho celebrated its 100th year of statehood in 1990, at the same time ushering in a decade in which the major environmental issue was nuclear waste contamination. The matter was highlighted by wildfires that raged in western states during the summer of 2000. One blaze charred the grounds of the Idaho National Engineering and Environmental Lab, a nuclear research and waste storage facility. Thirty thousand acres were burned before the fire was brought under control. But environmentalists, concerned citizens, and many Idaho lawmakers remained concerned that such storage facilities are vulnerable to natural disaster and pose a serious threat.
In 2001, 2002 and 2003, wildfires broke out in the west once again. In the summer of 2002, wildfires burned over 7.1 million acres of public and private land in the US, most of it in the west. Twelve western states, including Idaho, were the victims of severe wildfires that burned 2.7 million acres as of September 2003.