In June 1873, a Northern Pacific Railroad surveying party escorted by 1,500 soldiers, including the 7th Cavalry under the command of George Armstrong Custer, and 325 civilians, left Dakota Territory for the Yellowstone Valley to survey a route for the second transcontinental railroad. The Lakota Sioux and Cheyenne opposed the railroad and clashed with the soldiers on several occasions throughout July. On August 11, the expedition camped for a well earned rest just north of here. Five days later, some of the men sought relief from the summer heat by bathing in the Yellowstone River. Suddenly, six Lakota warriors hiding near Pompey's Pillar fired at them, prompting what one man later humorously recalled as an ensuing scramble for cover in which nude bodies scattered in all directions on the north bank for a hundred yards. The soldiers returned fire and eventually drove the Lakota away, and no one was killed in the skirmish. Afterward, the soldiers chose to bear the heat rather than risk another swim in the Yellowstone.