The Battle of Picacho Peak on April 15, 1862  was part of the American Civil War.  
Picacho Peak is near Tucson, Arizona and was the battle on the western front of the Civil War.  The battle was between a Union cavalry patrol of 13 men and a group of 10 Confederates.
The Union commander Lieutenant James Barrett and two of his men were killed and three others were wounded during the 90 minute battle. The remaining Union men retreated but Union forces from California later rode to Tucson and  captured the Confederate settlement there.