Idaho is a state in the Pacific Northwest 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 1.8 million and an area of 83,570 square miles (216,400 km2), Idaho is the 14th largest, the 13th least populous and the 7th least densely populated of the 50 U.S. states. The state’s capital and largest city is Boise.

For thousands of years Idaho has been inhabited by Native American peoples. In the early 19th century, Idaho was considered part of the Oregon Country, an area disputed between the United States and the British Empire.

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 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 states south include the Snake River Plain (which has most of the population and agricultural land). The states southeast incorporate 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.

Industries significant for the state economy include manufacturing, agriculture, mining, forestry, and tourism. Several science and technology firms are either headquartered in Idaho or have factories there, and the state also contains the Idaho National Laboratory, which is the country’s largest Department of Energy facility.

Idaho’s agricultural sector supplies many products, but the state is best known for its potato crop, which comprises around one-third of the nationwide yield. The official state nickname is the “Gem State”, which references Idaho’s natural beauty.

CLIMATE

Idaho’s climate varies widely. Although the state’s western border is about 330 miles (530 km) from the Pacific Ocean, the maritime influence is still felt in Idaho, especially in the winter when cloud cover, humidity, and precipitation are at their maximum extent.

This influence has a moderating effect in the winter where temperatures are not as low as would otherwise be expected for a northern state with predominantly high elevations. The maritime influence is least prominent in the state’s eastern part where the precipitation patterns are often reversed, with wetter summers and drier winters, and seasonal temperature differences are more extreme, showing a more semi-arid continental climate.

Idaho can be hot, although extended periods over 98 °F (37 °C) are rare, except for the lowest point in elevation, Lewiston, which correspondingly sees little snow. Hot summer days are tempered by the low relative humidity and cooler evenings during summer months since, for most of the state, the highest diurnal difference in temperature is often in the summer.

Winters can be cold, although extended periods of bitter cold weather below zero are unusual. Idaho’s all-time highest temperature of 118 °F (48 °C) was recorded at Orofino on July 28, 1934; the all-time lowest temperature of −60 °F (−51 °C) was recorded at Island Park Dam on January 18, 1943.