|Builder:||Fore River Shipyard, Quincy, Massachusetts|
|Laid down:||15 August 1918|
|Launched:||21 June 1920|
|Commissioned:||24 August 1921|
|Decommissioned:||10 February 1934|
|Struck:||12 December 1936|
|Fate:||Sunk off Pearl Harbor, 18 December 1938|
|Type:||S-class direct-drive diesel-electric submarine, S-1 type|
|Length:||219 ft 3 in (66.83 m)|
|Beam:||20 ft 8 in (6.30 m)|
|Draft:||15 ft 11 in (4.85 m) mean|
|Endurance:||20 hours at 5 kn (5.8 mph; 9.3 km/h)|
|Test depth:||200 ft (61 m)|
USS S-19 (SS-124) was a first-group (S-1 or "Holland") S-class submarine of the United States Navy. Her keel was laid down on 15 August 1918 by the Electric Boat Company in New York City, on subcontract to Bethlehem Shipbuilding Corporation's Fore River Shipyard in Quincy, Massachusetts. She was launched on 21 June 1920 sponsored by Ms. Genevieve Kittinger (daughter of Commander T. A. Kittinger, inspector of ordnance, U. S. N.), and commissioned on 24 August 1921 with Lieutenant Commander P.T. Wright in command.
After preliminary shakedown operations, S-19 was decommissioned and returned to the contractor on 8 March 1922 for further work to remedy defects revealed in her first weeks of operation. Upon her return to the United States Navy, S-19 recommissioned at Groton, Connecticut on 6 January 1923, with Lt. Cdr. William J. Butler in command.
S-19 operated off the northeastern coast of the United States from 1923–1930, taking part in fleet exercises off Panama in the early months of each year. This routine was interrupted in the foggy, early hours of 13 January 1925, when the submarine ran aground off Chatham, Massachusetts, on the southern coast of Cape Cod, after strong winds and unusually heavy seas had pushed her far from her course. She had departed Portsmouth Navy Yard the previous afternoon after overhaul, and was en route to New London, Connecticut. The United States Coast Guard cutters Tampa and Acushnet came to S-19's assistance, as did life-saving crews from two nearby Coast Guard stations. Heavy seas made it impossible to pass a line to the grounded submarine or to reach her by boat until late in the evening of 14 January, when a party from the Nauset, Massachusetts Coast Guard station succeeded in boarding. By the morning of 15 January, S-19's crew had been safely brought to shore. After strenuous effort by Navy tugs and the Coast Guard cutters, S-19 was finally freed from the shoal.
Repaired and returned to service with the fleet, S-19 continued her Atlantic operations until 22 October 1930, when she departed New London for the Pacific Ocean. The submarine arrived at Pearl Harbor on 7 December, and for the next three years operated out of Hawaii. She was decommissioned at Pearl Harbor on 10 February 1934, was struck from the Naval Vessel Register on 12 December 1936 and was towed to sea and sunk on 18 December 1938, in accordance with the terms of the Second London Naval Treaty.
S-19 was also featured in the Call of Cthulhu: Dark Corners of the Earth campaign Raid on Innsmouth.