For 10 points, name this U.S. city on the Missouri River, which is now named for an early fur trader and which is the capital of South Dakota?
When it was founded in 1880 as the western terminus of the Chicago and North Western Railway, it was named Mahto, the Sioux word for "bear".  Five years later, it would have become territory capital had it not been for a governor's veto.  For the 400 years before 1800, however, it was the site of the capital of the Arikara Indian nation.  For 10 points, name this U.S. city on the Missouri River, which is now named for an early fur trader and which is the capital of South Dakota?
When it was founded in 1880 as the western terminus of the Chicago and North Western Railway, it was named Mahto, the Sioux word for "bear".  
Pierre ("peer")