Pinkerton Ross Vaughn, Sr. (1841 – August 22, 1866) was a United States Marine Corps sergeant during the American Civil War. He was awarded the nation's highest military decoration for valor—the Medal of Honor, for his actions aboard the USS Mississippi during a battle with Confederate artillery batteries at Port Hudson, Louisiana on March 14, 1863. Vaughn is one of the first two Marines to be awarded the Medal of Honor in the history of the Marine Corps.