USS E-2 (SS-25) was an E-class submarine of the United States Navy. Originally named Sturgeon, the boat was launched on 15 June 1911 by the Fore River Shipyard, Quincy, Massachusetts; sponsored by Ms. Margaret Nelson Little; renamed E-2 on 17 November 1911; and commissioned on 14 February 1912, Ensign C. N. Hinkamp in command.