Roderick P. Connelly was born in 1841 in England, and later immigrated to the United States. He changed his name to Henry A. Thompson at the time he enlisted in the U.S. Marine Corps on July 21, 1863, at Philadelphia, Pennsylvania. Private Thompson served aboard the steam frigate USS Minnesota during the U.S. Civil War, and was awarded the Medal of Honor on June 22, 1865, for action aboard the Minnesota during the 2nd Battle of Fort Fisher on January 15, 1865. He was honorably discharged from the Marine Corps on July 12, 1867, and died on February 16, 1889. Henry Thompson is buried at the Cavalry Cemetery in Woodside, New York.

His Medal of Honor Citation reads:

On board the U.S.S. MINNESOTA in the assault on Fort Fisher, 15 January 1865. Landing on the beach with the assaulting party from his ship, Private Thompson advanced partly through a breach in the palisades and nearer to the fort than any man from his ship despite enemy fire which killed or wounded many officers and men. When more than two-thirds of the men became seized with panic and retreated on the run, he remained with the party until dark, when it came safely away, bringing its wounded, its arms and its colors.