Bighorn is near the Yellowstone County border where the Big Horn River flows into the Yellowstone. Bighorn is on ground that has been occupied almost continuously by white men since explorer William Clark camped there in July 1806. Manuel Lisa built a trading post there in 1807. In 1822 Col. W. H. Ashley built another post, Fort Van Buren, two miles below the mouth of the Big Horn River, where many westbound travelers stopped for a rest. General Gibbon with 450 men crossed the Yellowstone at this point in June 1876 as he was hurrying south to aid General Custer in a battle that had already been lost. (from Cheney's Names on the Face of Montana, Mountain Press Publishing Company)
