The section of the city along the Portneuf River was inhabited by the Shoshoni and Bannock peoples for several centuries before the arrival of Europeans in the early 19th century. In 1834, Nathaniel Jarvis Wyeth, a U.S. fur trader, established Fort Hall as a trading post north of the present location of the city. The post was later acquired by the Hudson's Bay Company and became an important stop on the Oregon Trail, a branch of which descended the Portneuf through the present-day location of the city. A replica of the Fort Hall trading post is now operated as a museum in southern Pocatello. Pocatello is the home of Idaho State University and the manufacturing facility of ON Semiconductor. Founded as an important stop on the first railroad in Idaho during the gold rush, the city later became an important center for agriculture. It is located along the Portneuf River where it emerges from the mountains onto the Snake River Plain, along the route of the Oregon Trail. The city is named after Chief Pocatello, a chief of the Shoshoni tribe who granted the right-of-way for the railroad across the Fort Hall Indian Reservation. The city is served by the Pocatello Regional Airport. Pocatello is the county seat and largest city of Bannock County, with a small portion on the Fort Hall Indian Reservation in neighboring Power County, in the southeastern part of the U.S. state of Idaho. It is the principal city of the Pocatello metropolitan area, which encompasses all of Bannock and Power counties. Pocatello is the fifth largest city in the state, just behind Idaho Falls. (Idaho Falls' population is 56,813.) In 2007, Pocatello was ranked twentieth on Forbes list of Best Small Places for Business and Careers.