In January, 1959, the Naval Security Group Detachment (NSGD), Groton was established. Ten months later, in October, the Naval Security Group designated its first Special Assistant for Naval Security Group matters and assigned him additional duty as Officer in Charge, Naval Security Group Detachment, Commander Submarine Force, U.S. Atlantic Fleet. One year later, the Chief of Naval Operations designated that position as Officer in Charge, Naval Detachment and Director of Intelligence Special Security Officer for Deputy Commander Submarine Force, U.S. Atlantic Fleet.
In October 1972, the Detachment was designated Naval Security Group Detachment Groton under the command of Commander, Naval Security Group Command. The Detachment was commissioned a Naval Security Group Activity (NSGA) on May 1, 1980. The official recommissioning date recorded in NAVSECGRU records was October, 1, 1980. NSGA Groton was re-established as NSG Detachment Groton in July, 2005.
On September 30, 2005, NSG Det Groton was administratively closed and was re-established on October 1, 2005 as the Navy Information Operations Detachment (NIOD) Groton, CT. In 2017, NIOD Groton was resubordinated under NIOC Maryland/CTF 1060 as CTG 1060.3, and in 2018 NIOD Groton was again resubordinated under NIOC Georgia/CTF 1050 as CTG 1050.3.
NIOD Groton performs Fleet Electronic Support through equipment installation, cyber certification, and deployment of highly trained Information Warfare personnel in Direct Support of U.S. Submarine operations.
NIOD Groton reports directly to NAVIOCOM Georgia and aligns under U.S. Fleet Cyber Command / U.S. TENTH Fleet.