John C. Donnelly (1839–1895) was a Union Navy sailor in the American Civil War and a recipient of the U.S. military's highest decoration, the Medal of Honor, for his actions at the Battle of Mobile Bay.
Born in 1839 in England, Donnelly immigrated to the United States and was living in New York when he joined the U.S. Navy.
At the Battle of Mobile Bay on August 5, 1864, he was among the crew of a small boat sent from Metacomet to rescue survivors of the USS Tecumseh, which had been sunk by a naval mine (then known as a "torpedo").
Despite intense fire, the boat crew was able to pull ten Tecumseh men from the water.
As a member of the boat's crew which went to the rescue of the U.S. Monitor Tecumseh when that vessel was struck by a torpedo in passing the enemy forts in Mobile Bay, 5 August 1864, Donnelly braved the enemy fire which was said by the admiral [ David Farragut ] to be "one of the most galling" he had ever seen and aided in rescuing from death 10 of the crew of the Tecumseh, eliciting the admiration of both friend and foe.