Idaho possesses a diverse and fascinating geographic and geologic history. From north to south Idaho is 479 miles long, undulating from mountains to valleys the state's entire length. In between are areas of high desert, deep canyons, rolling hills, lava flows, rock formations and innumerable mountain ranges covered in timber. Idaho is 83,574 square miles, which makes it the 14th largest of the 50 states. Elevations range from a low of 710 feet in the Snake River near Lewiston to the top of Mount Borah at 12,662 feet. The mean elevation is about 5,000 feet above sea level.
With 80 recognized mountain ranges, Idaho possesses some of the most rugged landscapes in the United States. National forests cover two-fifths of the state, some of which are set aside as designated wilderness areas with no roads. Idaho also lies on part of the Columbia Plateau, which extends out of Washington and Oregon across southern Idaho encompassing the vast and productive Snake River Plain. The Snake River winds across southern Idaho with occasional dams for power generation and water retention. Significant canyons along the Snake are at Twin Falls, south of Nampa and the most famous, Hells Canyon.
Idaho's rivers are a source of hydroelectric power and irrigation for the state's farmlands. Many rivers also accommodate a considerable rafting and jet boating industry in the summer months as licensed outfitters take clients on wild whitewater rides. The Middle Fork of the Salmon is the most pristine river journey in the state while the Payette River serves the population base in Boise. The Snake River in Hells Canyon is a popular spot to jet boat or raft while nearby upriver reservoirs are popular for camping and boating.
Glacial lakes such as Priest Lake, Lake Pend Oreille and Lake Coeur d'Alene rise above the heavily-wooded mountains in the northern part of the state. High alpine lakes in the Sawtooth Mountains, accessible only by hiking, are some of the loveliest on earth. It's no wonder that much of Idaho's attractiveness is tied to the outdoors.
The state's climate is affected by weather patterns off the Pacific Ocean which allow for a moderate climate. Idaho's climate varies widely depending more on elevation than latitude. Monthly average temperatures range from a high of 90.6 degrees Fahrenheit to a low of 15.1 degrees Fahrenheit. Summers are hot and dry in the arid southern basins while cold, snowy winters are common in central and northern Idaho. With an agreeable four-season climate, Idahoans enjoy river rafting in the summer and snow sports in the winter.
Some of Idaho's most interesting geological characters were created by cataclysmic ice age floods including America's deepest river gorge, Hells Canyon and the Snake River Canyon and Shoshone Falls at Twin Falls. More Idaho geologic features include the Great Rift National Landmark, a 50-mile series of earth fissures, Craters of the Moon National Monument lava flow, Mount Borah near Mackay, City of Rocks National Reserve near Almo, the ancient caldera that consists of Island Park, Mesa Falls on the Henrys Fork of the Snake River and Thousand Springs near Buhl.