Known for its casino and tourism industry, Reno is the county seat and most populous city of Washoe County and sits in the High Eastern Sierra foothills, in the Truckee River valley, on the eastern side of the Sierra Nevada. state of Nevada, along the Nevada-California border, about 22 miles (35 km) north from Lake Tahoe, known as 'The Biggest Little City in the World'. Reno ( / ˈ r iː n oʊ/ REE-noh) is a city in the northwest section of the U.S.