Casper is the only city in and the county seat of Natrona County, Wyoming, United States, although the county is home to a number of small towns and Casper suburbs. With a population of 49,644, Casper is the second largest city in Wyoming, after the capital city of Cheyenne with 53,011 inhabitants, according to the 2000 census. The city is located in east-central Wyoming at the foot of Casper Mountain, the north end of the Laramie Mountain Range, along the North Platte River. Interstate 25 approaches Casper from the North and South and is the main avenue of transportation to and from the city. The towns immediately adjacent to Casper are Mills, Wyoming, Evansville, Wyoming, Bar Nunn and Mountain View. Unincorporated areas include Allendale, Dempsey Acres, Red Buttes, Indian Springs, and several others.