Stanislaus Roy was born in France on November 12, 1846. Not much is known about his personal life or military career other than in 1876 he served in the U.S. 7th Cavalry Regiment under the command of Lieutenant Colonel George Armstrong Custer.

The Grant administration had tried to buy the Black Hills in what was the Montana Territory (now South Dakota) from the Sioux Nation, but the Lakota Sioux, northern Cheyenne and Arapaho joined together and refused to sell. Under the leadership of Sitting Bull, they also refused to be confined by reservation boundaries. Federal troops were sent to force the Sioux to return to their respective reservations. Lieutenant Colonel George Armstrong Custer and the 7th Cavalry were dispatched to accomplish this. Custer split his command into three battalions. Three companies under Major Reno to charge straight into the Sioux village, three companies under Captain Benteen to cut off the flight of any Sioux to the south and Custer took five companies under his personal command to attack the Sioux village from the north. On the day of the battle, approximately 6 to 7 thousand Indians (of which over 2,000 were warriors) were camped beside the Little Bighorn River. Custer did not realize the size of the enemy forces. He and the 209 men in his immediate command did not survive the day. An Indian counterattack pinned down the combined companies led by Reno and Benteen on a hilltop over four miles away. Of the approximately 400 cavalrymen besieged on the hilltop, 53 were killed and 60 wounded before the Indians ended their attack the next day. Thirteen survivors were awarded the Medal of Honor for their bravery in this battle.

Roy’s citation read: "The President of the United States of America, in the name of Congress, takes pleasure in presenting the Medal of Honor to Sergeant Stanislaus Roy, US Army, for extraordinary heroism in 25 June 1876, while serving with Company A, 7th US Cavalry, in action at Little Big Horn, Montana. Sergeant Stanislaus brought water to the wounded at great danger to life and under a most galling fire of the enemy."

Roy died on February 10, 1913 at the Columbus Barracks, Ohio. He is buried in Green Lawn Cemetery in Columbus.

References:
Congressional Medal of Honor Society
Hall of Valor Project – Army
Multiple Wikipedia searches.