As the officer in charge of the only unit to survive the Battle of the Little Bighorn, Marcus Reno has remained a subject of controversy for more than a century. Born in Illinois in 1834, Reno attended West Point and served as a cavalry officer in the Civil War. In 1871 he was made a major in the Seventh Cavalry under the command of George Armstrong Custer, and took part in Custer's 1874expedition through the Black Hills.

Two years later, when General Alfred Terry was planning the campaign against Sitting Bull and his followers in the Powder River country of Montana, Reno was dispatched on a scouting mission through the region and reported back with evidence that a large Indian encampment had recently moved upstream along Rosebud Creek. This intelligence led Terry to order a "hammer-and-anvil" operation, with Colonel John Gibbon'sinfantry taking the part of the anvil against which the hammer of Custer's Seventh Cavalry would drive the enemy and smash them.

Picking up the trail Reno had discovered on the Rosebud, Custer, however, moved too quickly and located Sitting Bull's huge encampment along the Little Bighorn River on June 25, before Gibbon's troops had reached their position. Nonetheless, rather than risk losing the opportunity, Custer ordered an attack. As he rode toward the encampment, he saw a group of warriors racing ahead of him, and fearing that they would alert the others, and that the whole encampment would flee before he could reach it, Custer ordered Reno to pursue the warriors and bring them to battle, promising that he and the rest of the command would soon follow.

As Reno led his troops toward the encampment, however, a rapidly growing band of warriors rode out to meet him. He ordered his men to dismount and fight on foot, but the number of warriors continued to grow and Reno found himself driven back into a defensive position within a stand of timber. Still the number of warriors increased, and with no sign of the promised support from Custer, Reno ordered a retreat to a more defensible position on the high bluffs along the Little Bighorn River. In the confusion of battle, this retreat became a rout in which one third of Reno's battalion was lost, but he and his men did manage to reach the bluffs, where they were joined by a second battalion that Custer had sent to scout the area.

While Custer and his troops suffered annihilation, some of Reno's men tried to move downstream along the river, where they hoped to break free of the battle. Eventually, the entire battalion joined in this attempt, but they were soon driven back when warriors returning from the fight with Custer mounted a fresh attack against them. Finally, Reno and his men retreated once more to the bluffs, where they took up entrenched positions and fought off successive attacks for nearly thirty-six hours, until the approach of Gibbon's troops caused Sitting Bull and his followers to withdraw on the evening of June 26. The next day, Gibbon himself, accompanied by General Terry, arrived on the battlefield and rescued Reno and the other survivors.

Many in the army and in the general public refused to believe that mere Indians could destroy a commander like Custer unaided by American blunders, and they sought to blame Reno for the defeat at the Little Bighorn. They pointed to Reno's defensive reaction when his assault on Sitting Bull's encampment was met with unexpected resistance, to his evident loss of command at several points during the course of the battle and to the fact that he had clung to his defensive position even while Custer's forces were being surrounded and destroyed.

In 1879, a military court of inquiry officially cleared Reno of charges of cowardice, but the following year he was court-martialed on several unrelated charges by an officer whose son had died at the Little Bighorn. By the time of his death in 1889, Marcus Reno had become the antithesis of the gallant Custer in the popular imagination, a disgrace to the noble code of the United States cavalry who was unworthy to lie buried beside the brave men who had died at "Custer's Last Stand." In 1967, however, a military Board of Review re-examined Reno's court-martial and reversed history's judgment against him by changing the status of his discharge to honorable and ordering the reinternment of his remains in the sacred ground of the Little Bighorn cemetery.