Idaho is a state in the northwestern region of the United States. It borders the state of Montana to the east and northeast, Wyoming to the east, Nevada and Utah to the south, and Washington and Oregon to the west. To the north, it shares a small portion of the Canadian border with the province of British Columbia. With a population of approximately 1.7 million and an area of 83,569 square miles (216,440 km2), Idaho is the 14th largest, the 12th least populous and the 7th least densely populated of the 50 U.S. states.
Idaho prior to European settlement was inhabited by Native American peoples, some of whom still live in the area. In the early 19th century, Idaho was considered part of the Oregon Country, an area disputed between the U.S. and the United Kingdom. It officially became U.S. territory with the signing of the Oregon Treaty of 1846, but a separate Idaho Territory was not organized until 1863, instead of 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). The state’s 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 most of any state.