Idaho (/ˈaɪdəhoʊ/ ^ⓘ EYE-də-hoh) is a landlocked state in the Mountain West subregion of the United States. It shares a small portion of the Canada–United States border to the north, with the province of British Columbia. It borders Montana and Wyoming to the east, Nevada and Utah to the south, and Washington and Oregon to the west. The state's capital and largest city is Boise. With an area of 83,570 square miles (216,400 km²), Idaho is the 14th largest state by land area. With a population of approximately 1.8 million, it ranks as the 13th least populous and the 6th least densely populated of the 50 U.S. states.

For thousands of years, and prior to European colonization, Idaho has been inhabited by native peoples. In the early 19th century, Idaho was considered part of the Oregon Country, an area of dispute between the U.S. and the British Empire. It officially became a U.S. territory with the signing of the Oregon Treaty of 1846, but a separate Idaho Territory was not organized until 1863, instead being included for periods in Oregon Territory and Washington Territory. Idaho was eventually admitted to the Union on July 3, 1890, becoming the 43rd state.

Forming part of the Pacific Northwest (and the associated Cascadia bioregion), Idaho is divided into several distinct geographic and climatic regions. The state's north, the relatively isolated Idaho Panhandle, is closely linked with Eastern Washington, with which it shares the Pacific Time Zone—the rest of the state uses the Mountain Time Zone. The state's south includes the Snake River Plain (which has most of the population and agricultural land), and the southeast incorporates part of the Great Basin. Idaho is quite mountainous and contains several stretches of the Rocky Mountains. The United States Forest Service holds about 38% of Idaho's land, the highest proportion of any state. (Full article...)