In early April 1865, during the Battle of Sailor's Creek (also known as "Sayler's Creek") in Virginia, Cunningham performed the act of valor for which he would later be awarded the U.S. Medal of Honor. Four decades later, during an interview for the book, "Deeds of Valor from Records in the Archives of the United States Government: How American Heroes Won the Medal of Honor", he spoke about what happened that day: