12 May 1865 – The Battle of Palmito Ranch is generally considered as the final battle of the American Civil War, being the last engagement of any significance involving casualties. The battle was fought on the banks of the Rio Grande, east of Brownsville, Texas, and a few miles from the seaport of Los Brazos de Santiago (now known as Matamoros).
Union and Confederate forces in Southern Texas had been observing an unofficial truce, when Union Colonel Theodore H. Barrett ordered an attack on an enemy camp near Fort Brown, for reasons unknown. (Some claimed that Barrett was eager for his first chance of action before the war ended.) Although they took some prisoners, the attack was repulsed the next day by Confederate Col. John Salmon Ford near Palmito Ranch, and the battle is claimed as a Confederate victory.
Estimates of casualties are not dependable, but Union Private John J. Williams of the 34th Indiana (Photo) is believed to have been the last of the close to 655,000 combat deaths of the war