J.C. Hobbs was an American inventor and engineer who created a key part of the valves used in the K-25 gaseous diffusion plant in Oak Ridge, Tennessee. He was a prominent graduate of Carnegie Mellon University in Pittsburgh and was vice-president of the Diamond Alkali Company.
Hobbs was brought on to the Manhattan Project by the head of the Kellex Corporation, Percival Keith, to improve the piping system in the K-25 plant.