This sums it up about a neat and concise as anything I have seen. If incorrect, please feel free to correct.

"General Philip H. Sheridan concluded that George A. Custer had made several important mistakes at the Little Big Horn. He argued that after their seventy mile journey, Custer's men were too tired to fight effectively. Custer had also made a mistake in developing a plan of attack on the false assumption that the Sioux and Cheyenne would attempt to escape rather than fight the soldiers.

Sheridan also criticized Custer's decision to divide his men into three groups: "Had the Seventh Cavalry been held together, it would have been able to handle the Indians on the Little Big Horn." His final mistake was to attack what was probably the largest group of Native Americans ever assembled on the North American continent. President Ulysses Grant agreed with this assessment and when interviewed by the New York Herald he said: "I regard Custer's Massacre was a sacrifice of troops, brought on by Custer himself, that was wholly unnecessary"."