The complex is under US Army Intelligence and Security Command (INSCOM) command on behalf of the US National Security Agency (NSA) and is officially known as Subunit 1 operated by USMC G Company. After a large basement expansion at the complex in 2002 it hosted an important SIGINT processing, analysis and reporting center.
As the entire SIGINT unit relocated to the Lucius D.Clay Barracks at Wiesbaden in 2016 as part of the new Information Processing Center (IPC) which is part of the recently established US Consolidated Intelligence Center (CIC).  the status of the Dagger complex has been changed into a military datacenter. All processing, analysis and reporting activities are now taking place in WIesbaden.
This unit started as 66th CIC Detachment based in Stuttgart at its reactivation in 1951. In 1952 redesignated 66th CIC Group and in 1977 after an armywide intel reorganisation assigned to INSCOM. In 1986 relocated to Augsburg being redesignated 66th MI Brigade. In 1995 temporarily redesignated 66th MI Group. Relocated again to Dagger compound Darmstadt as of 1998. Definitely 66th MI Group in 2002 until its final redesignation 66th MI Brigade and its staffing relocation to Wiesbaden Army Airfield in 2008.
Until 2015 the Dagger complex based the European Cryptologic Center (ECC) structured as F2 which had been operated by mixed operational crews consisting of specialized personnel from NSA, US Army 66th Intel Bde, USAF 693 ISR Grp and USMC Crypto Suppt Bn; all under command of 66th Military Intelligence Brigade then awaiting their relocation to Wiesbaden. These specialists used to interprete and analyse all intercepted metadata obtained by
- the ICEBOX  (2003-2008) facility constructed at former Darmstadt Army Airfield at grid 49°51'19"N 8°35'12"E and
- the TENCAP (2005-2009) facility constructed at former Finthen Army Airfield at grid 49°58'8"N 8° 9'46"E.
Above mentioned facilities have been removed respectively by the end of 2009 and 2013.
In 2015, the Peng Collective operated a airborne leaflet strike over the facility as part of their Intelexit program, to call the employees to quit their job in case of ethical or psychological distress. Shortly after the drop of the leaflets, the association's website was blocked on computers within the complex.
- Colorado Cryptologic Center
- Georgia Cryptologic Center
- Hawaii Cryptologic Center
- Texas Cryptologic Center
- Christian Fuchs; John Goetz; Frederik Obermaier; Bastian Obermayer & Tanjev Schultz. "Frankfurt: An American Military-Intel Metropolis". Süddeutsche Zeitung. Retrieved 21 December 2013.
- Waid, Matthew (July 22, 2013). "The European Cryptologic Center at Darmstadt, Germany". Retrieved July 15, 2015.
- Charlie Coon (2003-10-07). "66th MIG assets to begin moving to Darmstadt". The Stars and Stripes. Retrieved 2013-07-14.
- McLaughlin, Jenna (October 5, 2015). "Drone Flies Over NSA Complex in Germany, Dropping Leaflets". The Intercept.
- "Protestaktion bei Darmstadt: Drohne wirft Flugblätter über NSA-Komplex ab" [Drone Drops Leaflets Over NSA Complex]. Spiegel Online (in German). 5 October 2015.
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