Tier 1: Special Mission Unit (SMU)

Author: Eric Sof


Tier 1 (Tier One) in the United States military is often referred to as the Special Mission Unit or Special Missions Unit (SMU). It is mainly used to describe some military Special Operations Forces. Special mission units have been involved in high-profile military operations such as Operation Neptune Spear (the killing of Osama Bin Laden).

Tier 1 Special Mission Units are closed teams that are staffed by invitation. They fall under the ultra-secret Joint Special Operations Command (JSOC), which is within USSOCOM. They are the best of the best of the best. They frequently staff teams coordinated and commanded by the CIA’s Special Activities Center (SAC) in teams called Special Operations Groups when full political deniability is required (clandestine missions).

Tier 1 units in the US military

There are only four acknowledged Tier 1 special mission units in the United States military:

Delta Force

Delta Force’s full name is 1st Special Forces Operational Detachment—Delta. It is also known as CAG (Combat Applications Group). The unit was founded in 1977, and it is part of the US Joint Special Operations Command, based at Fort Bragg, North Carolina. Delta Force is one of the most secret operations units in the United States military. It belongs under the U.S. Army branch.


The U.S. Navy counterpart to Delta Force is DEVGRU or SEAL Team 6. Their personnel is taken from the NAVSPECWARCOM SEAL teams. JSOC Maritime counter-terrorism specialists trained to rescue hostages from ships, oil rigs, fight pirates, assault and exploit High-Value Targets (HVT) for inclusion in the High Payoff Target List (HPT).

24th Special Tactics Squadron

The 24th Special Tactics Squadron is one of the Special Tactics units of the United States Air Force Special Operations Command (AFSOC). It is the US Air Force component of Joint Special Operations Command. It is Airforce’s counterpart to the Delta Force and DEVGRU.

Intelligence Support Activity (ISA)

The US Army Intelligence Support Activity (USA ISA or US ISA) is a US Army Special Ops unit part of the Joint Special Operations Command. It is tasked to collect actionable intelligence in advance of missions by other US special operations forces, especially 1st SFOD-D and DEVGRU, in counter-terrorist operations.


The operators assigned to the Tier 1 units are the creme de la creme of special operations forces. Usually, admittance into Tier 1 units is only possible after service in a Tier 2 unit. For example, as for DEVGRU, one must also be ex-spec ops, unlike regular SEAL Teams whose admittance does not require prior military service.

In Delta Force, most of the unit comes from either RB or SF, but it’s not a prerequisite. Operators have come from traditional infantry and non-infantry units. The only requirement is that if you are not 11B or 18 series after your initial 3-year commitment, you will reclass to one of these specialties.

Tier 1: Operators from the Blue Squadron brandishing flag - Development Group (DEVGRU, Seal Team 6)
Tier 1 – DEVGRU – Blue Squadron – (Development Group, Seal Team 6) (Photo: XY)

The skills set that Tier 1 applicants would have due to prior service in Tier 2 units would be impeccable marksmanship skills, explosives skills and knowledge of military strategy tactics, etc. Once fully trained as a Tier 1 operator, the soldier would have been trained in psychological training to resist torture/interrogation and in evasion tactics such as Survival, Evasion, Resistance, and Escape (SERE) training.

At some points, there is also possible that members of the Tier 2 units, like those from the Army’s 75th Ranger Regiment, Army Special Forces, and 160th SOAR, are controlled by JSOC when deployed as part of JSOC Task Forces such as Task Force 121 and Task Force 145.

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1 thought on “Tier 1: Special Mission Unit (SMU)”

  1. The Joint Special Operations Command also oversees the Special Mission Units of U.S. Special Operations Command. These are elite special operations forces units that perform highly classified activities. So far, only four SMUs have been publicly disclosed:

    The Army’s 1st Special Forces Operational Detachment-Delta (Delta Force)
    The Navy’s Naval Special Warfare Development Group (DEVGRU / SEAL Team 6)
    The Air Force’s 24th Special Tactics Squadron[7] (24 STS)
    The Army’s Intelligence Support Activity (ISA)

    Additionally, a fifth unit, the Army Ranger’s Regimental Reconnaissance Company (RRC), part of USASOC, has been referred to as a SMU.