Custer divided his regiment into three battalions. He retained five companies under his command and assigned three companies each to his immediate Officers Maj. Marcus A. Reno and Capt. Frederick Benteen. One company was assigned to guard the slow-moving pack train.
Benteen was ordered to scout the bluffs to the south, while Custer and Reno headed toward the Indian camp in the valley of the Little Bighorn. When near the river, Custer turned north toward the lower end of the encampment. Reno, ordered to cross the river and attack, advanced down the valley to strike the southern end of the camp. As he neared the camp a large force of Lakota warriors rode out from the southern edge of the encampment to intercept him. Forming his men into a line of battle, Reno would soon be overwhelmed. Outflanked and forced in the timber. Eventually they cross the river and take up defensive positions on the bluffs beyond. Here he was joined by Benteen, who had hurried forward under orders from Custer to " come on; Big village, be quik, bring packs". Reno and Benteen's command are held down for another two days by the Sioux and Cheyenne warriors. On the afternoon of the 26th, to their surprise the warriors broke off attacking. The Indians had learned that a large force of soldiers were coming down from the north. The Indian people packed up and left the valley heading south.
In the meantime, Custer had ridden into history and legend. His Movements after separating from Reno have never been determined, but vivid accounts of the battle by Indians who participated in it tell how his command was surrounded and destroyed in fierce fighting. Northern Cheyenne, Chief Two Moons, recalled that "the shooting was quick, quick. Pop-pop-pop very fast. We circled all around him-swirling like water around a stone. We shoot, we ride fast, we shoot again. Soldiers drop, by rapping clapping of his his hands and says "in a matter of minutes it was over".
In the battle, the 7th Cavalry lost five companies (C, E, F, I, and L) under Custer, about 210 men. Of the other companies of the regiment under Reno and Benteen, 53 men were killed and 52 wounded. The Indians lost at least 60 or more.
The Sioux and Cheyenne scattered, some going north, some going south. Although the Sioux and Cheyennes won the battle that day but subsequently they lost the war against the military's effort to end their independent, nomadic way of life. Most of them returned to the reservation and surrendered in the next few years.