Submarine Squadron 4 (also known as SUBRON 4 or CSS-4) was raised by the United States Navy in 1930. Since 9 July 1997, the squadron has been based at the Naval Submarine Base New London, Groton, Connecticut, United States of America. Composition The current submarines assigned to the squadron include: Los Angeles-class submarines USS Hartford (SSN-768) Virginia-class submarines USS Virginia (SSN-774) USS California (SSN-781) USS North Dakota (SSN-784) USS Colorado (SSN-788) USS Indiana (SSN-789) USS South Dakota (SSN-790) USS Delaware (SSN-791) – Commissioned 4 April 2020 USS Vermont (SSN-792) – Commissioned 18 April 2020 Pearl Harbor 1930 to 1945 In 1930, the squadron was raised at the Pearl Harbor submarine base. Its commanding officers to 1945 included the following captains: W. K. Wortman (1930 - 1932), H. W. Osterhas (1932 - 1934), R. A. Kock (1934 - 1936), R. S. Culp (1936 - 1938), Francis W. Scanland (1938 - November 1940), Worrall R. Carter (November 1940 - 7 December 1941), Freeland A. Daubin (7 December 1941 - 6 February 1942), Robert H. English (19 March 1942 - 10 May 1942), John M. Haines (18 May 1942 - 24 June 1942), John H. Brown Jr. (14 July 1942 - 4 November 1943), Charles D. Edmunds (12 May 1943 - 31 August 1943), Leon J. Huffman (11 September 1943 - 27 September 1943), Charles B. Momsen (12 November 1943 - 2 July 1944), Clarence E. Aldrich (1 December 1943 - 27 December 1943), Charles F. Erck (July 1944 - 12 October 1944) William V. O'Regan (15 October 1944 - 24 May 1945) It was Captain Freeland Allan Daubin who was in command during the Japanese attack on Pearl Harbor on 7 December 1941. While stationed there, the squadron comprised Submarine Squadron 4 Headquarters, at Pear Harbour Submarine Base USS Litchfield (DD-336), underway south of Oahu – Tactical Flagship USS Widgeon (ASR-1) Submarine Division 41, at Naval Base San Diego, commanded by Commander Forrest Marmaduke O'Leary USS S-18 (SS-123) (F) USS S-23 (SS-128) USS S-27 (SS-132), being overhauled at Mare Island Naval Shipyard USS S-28 (SS-133), being overhauled at Mare Island Naval Shipyard USS S-34 (SS-139) USS S-35 (SS-140) Submarine Division 42, at Pear Harbour Submarine Base, commanded by Commander Clifford Harris Roper USS Argonaut (SM-1) (F), on patrol in the vicinity of Midway Atoll USS Narwhal (SS-167) (F) USS Nautilus (SS-168), at Mare Island Naval Shipyard USS Dolphin (SS-169) USS Cachalot (SS-170)