The 621st was established on 24 June 1994 as the 621st Air Mobility Operations Group before being activated on 22 July of that year at McGuire Air Force Base (part of Joint Base McGuire–Dix–Lakehurst since 2009).
It was expanded into the 621st Contingency Response Wing on 1 March 2005.
The 621st included four groups, eight squadrons and ten geographically separated operating locations aligned with major US Army and Marine Corps combat units.
The wing maintains a ready corps of light, lean and agile mobility support forces able to respond as directed by the 18th Air Force at Scott Air Force Base, Ill., in order to meet Combatant Command wartime and humanitarian requirements.

Following the 2010 Haiti earthquake of 12 January, the 817th Contingency Response Group deployed to Toussaint L'Ouverture International Airport, Port-au-Prince, Haiti in support of Operation Unified Response.
Before the earthquake, Toussaint L'Ouverture handled an average of 20 flights a day.
Immediately following the earthquake this number jumped dramatically.
At its peak on 19 January, more than 160 aircraft landed and were safely unloaded by the CRW—an 800 percent increase in air traffic from pre-disaster levels.

In early 2010, Airmen from the 571st Contingency Response Group and 819th Global Support Squadron deployed to Camp Marmal, Mazar-i-Sharif, Afghanistan to provide aerial cargo handling support for the Operation Enduring Freedom logistics surge.
The 816th Contingency Response Group was inactivated on 11 June 2010.
In August 2010, 30 Airmen from the 818th Contingency Response Group deployed as a Contingency Response Element, or CRE, to Chaklala Airbase, Pakistan.
Once deployed, they provided additional aerial port capabilities to increase aircraft loading efficiency for the Pakistan Air Force's Central Flood Relief Cell.

Airmen from the 621st Contingency Response Group deployed thrice in support of Operation Inherent Resolve, in 2015, they deployed to Iraq where it established an airstrip at al-Taqaddum to support coalition forces in the Battle for Ramadi.
In 2016, the group established the Kobani airfield in Syria and also set up an airfield at Qayarrah West in Iraq to support coalition forces in the Battle of Mosul.
In November 2016 Airman from the group with a contingent of civil engineers, intelligence personnel and security forces were temporarily deployed to expand and modify the airstrip that the Airmen had established at an air base where they deployed to near Kobani, so it can be used effectively to assist in the offensive to retake Raqqa from ISIS.
The airbase gives the US an additional location for its aircraft to support U.S. and other anti-ISIS forces, but it had been used by US forces limitedly due to the condition of the runway which restricted what types of aircraft could land there.
General Carlton Everhart II, commander of US Air Mobility Command, said that the base enables aircraft to deliver critical supplies, equipment and help position forces, he added that airmen from the 621st group have supported anti-ISIS coalition forces on the ground in Syria.
The 621st was established on 24 June 1994 as the 621st Air Mobility Operations Group before being activated on 22 July of that year at McGuire Air Force Base (part of Joint Base McGuire–Dix–Lakehurst since 2009). It was expanded into the 621st Contingency Response Wing on 1 March 2005. The 621st included four groups, eight squadrons and ten geographically separated operating locations aligned with major US Army and Marine Corps combat units. The wing maintains a ready corps of light, lean and agile mobility support forces able to respond as directed by the 18th Air Force at Scott Air Force Base, Ill., in order to meet Combatant Command wartime and humanitarian requirements. 
Following the 2010 Haiti earthquake of 12 January, the 817th Contingency Response Group deployed to Toussaint L'Ouverture International Airport, Port-au-Prince, Haiti in support of Operation Unified Response. Before the earthquake, Toussaint L'Ouverture handled an average of 20 flights a day. Immediately following the earthquake this number jumped dramatically. At its peak on 19 January, more than 160 aircraft landed and were safely unloaded by the CRW—an 800 percent increase in air traffic from pre-disaster levels.
In early 2010, Airmen from the 571st Contingency Response Group and 819th Global Support Squadron deployed to Camp Marmal, Mazar-i-Sharif, Afghanistan to provide aerial cargo handling support for the Operation Enduring Freedom logistics surge. The 816th Contingency Response Group was inactivated on 11 June 2010. In August 2010, 30 Airmen from the 818th Contingency Response Group deployed as a Contingency Response Element, or CRE, to Chaklala Airbase, Pakistan. Once deployed, they provided additional aerial port capabilities to increase aircraft loading efficiency for the Pakistan Air Force's Central Flood Relief Cell.
Airmen from the 621st Contingency Response Group deployed thrice in support of Operation Inherent Resolve, in 2015, they deployed to Iraq where it established an airstrip at al-Taqaddum to support coalition forces in the Battle for Ramadi. In 2016, the group established the Kobani airfield in Syria and also set up an airfield at Qayarrah West in Iraq to support coalition forces in the Battle of Mosul. In November 2016 Airman from the group with a contingent of civil engineers, intelligence personnel and security forces were temporarily deployed to expand and modify the airstrip that the Airmen had established at an air base where they deployed to near Kobani, so it can be used effectively to assist in the offensive to retake Raqqa from ISIS. The airbase gives the US an additional location for its aircraft to support U.S. and other anti-ISIS forces, but it had been used by US forces limitedly due to the condition of the runway which restricted what types of aircraft could land there. General Carlton Everhart II, commander of US Air Mobility Command, said that the base enables aircraft to deliver critical supplies, equipment and help position forces, he added that airmen from the 621st group have supported anti-ISIS coalition forces on the ground in Syria.
621st Contingency Response Wing