Ulysses S. Grant issued his famous ultimatum at Fort Donelson, Tennessee: “No terms except unconditional and immediate surrender can be accepted. I propose to move immediately upon your works.” Confederate forces accepted. (17,398 casualties)
The Dakota Conflict began in Minnesota between US troops and several eastern bands of Dakota or Santee Sioux along Minnesota River. Between 300 and 800 white civilians and an unknown number of American Indians were killed in the conflict, which continued through September.