Billings, located in the south-central portion of Montana is rapidly growing. A 2006 census shows the city's population has grown to 98,234, making it the most populous city in Montana. Billings is the seat of Yellowstone County. It is nicknamed the Magic City because of its rapid growth from its founding as a railroad town in 1882. The city's proximity to Yellowstone National Park and the area where the Battle of the Little Bighorn was fought draws a large number of tourists, especially during the summer months. Traffic in recent years is largely due to Billings being on the most significant highway in Montana, Interstate 90.