On the morning of January 23, 1870, troops of the 2nd U.S. Cavalry attacked a Piegan Indian village on the Marias River in Montana Territory, killing many more than the army’s count of 173, most of them women, children, and old men. The village was afflicted with smallpox. Worse, it was the wrong encampment. Intended as a retaliation against Mountain Chief’s renegade band, the massacre sparked public outrage when news sources revealed that the battalion had attacked Heavy Runner’s innocent village—and that guides had told its inebriated commander, Major Eugene Baker, he was on the wrong trail, but he struck anyway. Remembered as one of the most heinous incidents of the Indian Wars, the Baker Massacre has often been overshadowed by the better-known Battle of the Little Bighorn and has never received full treatment until now.