U.S. Army

The 4th Adjutant General (Personnel Processing), or 4th AG (PP), was a vital administrative unit located at Fort Carson, Colorado. Activated to support the growing personnel needs of the installation and its assigned units, the 4th AG (PP) specialized in processing, accountability, and management of soldiers arriving at or departing from Fort Carson. The unit played a critical role in ensuring the smooth transition of personnel during major deployments, training rotations, and peacetime operations. Throughout its service, the 4th AG (PP) upheld the Army's standards for personnel readiness and administrative efficiency before its eventual inactivation as part of Army restructuring initiatives.

The 4th Army HQ has a storied history, originally established during World War I as part of a broader expansion of national military forces. Throughout the 20th century, the 4th Army HQ played a key role in coordinating field operations, logistics, and strategic planning in both world wars and various regional conflicts. In World War II, the unit was instrumental in overseeing several major campaigns, contributing to the overall effectiveness of allied operations. Today, the 4th Army HQ continues to serve as a vital command center, adapting to modern warfare and supporting both domestic and international missions.

The 4th Battalion, 76th Artillery traces its lineage to the 76th Field Artillery Regiment, originally constituted in the early 20th century. Reactivated and reorganized several times, the battalion saw significant service during the Vietnam War, providing critical fire support for infantry operations and earning campaign streamers for its actions. Throughout the Cold War, the unit was stationed in Europe as part of NATO forces, maintaining readiness during periods of heightened tension. The 4th Battalion, 76th Artillery is recognized for its professionalism and dedication, upholding a proud tradition of artillery excellence within the U.S. Army.

The 4th Combat Engineer Battalion is a unit of the United States Marine Corps Reserve, originally activated in 1943 during World War II. The battalion participated in the Pacific campaign, providing critical engineering support during the battles of Guam and Iwo Jima. Reactivated and reorganized several times over the decades, the unit has supported operations in the Gulf War, Iraq, and Afghanistan, excelling in mobility, survivability, and countermobility tasks. Today, the 4th Combat Engineer Battalion continues to serve as an essential engineering force within the Marine Corps Reserve, supporting both combat and humanitarian missions worldwide.

The 4th Maintenance Squadron (4th MXS) is a vital support unit within the United States Air Force, primarily assigned to the 4th Fighter Wing at Seymour Johnson Air Force Base, North Carolina. Established to provide comprehensive maintenance support, the squadron specializes in aircraft repair, component maintenance, and munitions handling for F-15E Strike Eagle operations. Throughout its history, the 4th MXS has played a crucial role in sustaining combat readiness during major conflicts and peacetime operations, including deployments in support of Operations Desert Storm, Enduring Freedom, and Iraqi Freedom. The unit’s commitment to excellence ensures the operational effectiveness and safety of the wing’s aircraft fleet, making it an indispensable part of Air Force mission success.

The 4th Sustainment Brigade, nicknamed the "Wranglers," is a logistics unit of the United States Army, headquartered at Fort Carson, Colorado. It was originally constituted in 2004 as part of the Army’s modular transformation, designed to provide comprehensive sustainment support to the 4th Infantry Division and other assigned units. Since its activation, the brigade has deployed multiple times in support of Operations Iraqi Freedom and Enduring Freedom, providing critical supply, maintenance, transportation, and logistical services. The 4th Sustainment Brigade continues to play a vital role in ensuring mission readiness and support for deployed forces worldwide.

The 4th Battalion, 61st Air Defense Artillery (4-61 ADA) traces its lineage to the 61st Coast Artillery Regiment, originally constituted in 1917. Reactivated and reorganized several times throughout the 20th century, the battalion served in various air defense roles during World War II, providing critical anti-aircraft protection in the European Theater. During the Cold War, 4-61 ADA operated advanced missile systems, such as the Nike Hercules, to defend against potential aerial threats in Europe and the United States. The unit was eventually inactivated as part of broader realignments in U.S. Army air defense structure, but its legacy endures as part of the proud history of American air defense artillery.

The 5th Battalion, 15th Infantry Regiment (5/15), is a distinguished unit that has served under the 1st Infantry Division of the United States Army. The 15th Infantry Regiment traces its origins back to the Civil War, with a proud lineage in major conflicts including World Wars I and II, Korea, and Vietnam. As part of the 1st Infantry Division, 5/15 played vital roles in various operations, demonstrating valor and professionalism in both combat and peacekeeping missions. Today, the regiment continues to uphold its legacy of excellence, serving with honor in support of U.S. Army missions worldwide.

The 501st Air Defense Artillery (ADA) traces its lineage back to its constitution in 1923 as the 501st Artillery (Antiaircraft), Coast Artillery Corps. Activated for World War II, the unit saw service in key campaigns in the European Theater, providing critical air defense against Axis aircraft. Over the decades, the 501st underwent multiple reorganizations, eventually becoming part of the U.S. Army’s modern air defense command structure. Today, the 501st ADA continues its mission, operating advanced missile defense systems to protect allied forces and assets against aerial and missile threats.

The 503rd Administrative Company was a support unit in the United States Army, primarily tasked with providing administrative, personnel, and logistical support to larger combat formations. The unit was often attached to the 503rd Infantry Regiment, famously known as the "Rock Regiment," which saw action in World War II during the liberation of Corregidor in the Philippines. The 503rd Admin Company played a critical behind-the-scenes role, ensuring smooth operations by managing records, mail, and essential supplies for frontline troops. Over the years, the company adapted to evolving military needs, supporting airborne and infantry operations until its eventual inactivation or integration during later force restructuring.

The 504th Administration Company was a support unit in the United States Army, initially activated to provide essential administrative and personnel services to larger combat formations. Throughout its history, the unit played a crucial role in managing records, mail, finance, and other vital functions, ensuring that frontline troops remained effective and supported. The 504th often operated in conjunction with major divisions during deployments and training exercises, adapting to the evolving logistical needs of the Army. Over time, as the Army’s structure and support requirements changed, the company was eventually reorganized or inactivated, with its legacy carried on by successor units in Army administration and support.

The **507th HEM**, or 507th Heavy Equipment Maintenance Company, is a U.S. Army unit specialized in maintaining and repairing heavy tactical vehicles and equipment. Activated in the latter half of the 20th century, the unit has provided vital support in various operations by ensuring the readiness and reliability of military hardware. One of its most notable moments came during Operation Iraqi Freedom in 2003, when elements of the 507th were ambushed near Nasiriyah; this incident led to widespread attention and highlighted the dangers support units can face in combat zones. The 507th HEM continues to serve as a crucial component of Army logistics, upholding a tradition of technical expertise and resilience under challenging conditions.

The 508th Supply and Service (S&S) Company was a logistical unit in the United States Army, activated during the Vietnam War era. Its primary mission centered on providing essential supply, transportation, and support services to combat and support units in its area of operations. The company was responsible for distributing food, fuel, ammunition, and other critical materials, ensuring operational readiness and sustainment for frontline and rear-echelon forces. Throughout its deployment, the 508th S&S Company played a vital role in maintaining the logistical flow, contributing significantly to overall mission success before its eventual inactivation as part of post-war force reductions.

The 520th Engineer Company is a U.S. Army unit with a distinguished record of service in both combat and peacetime operations. Originally activated during World War II, the company has provided vital engineering support, including construction, route clearance, and mobility operations. Over the decades, the 520th has deployed to various theaters, including Iraq and Afghanistan, where its soldiers have built infrastructure and ensured safe passage for coalition forces. The company's commitment to excellence and adaptability has earned it multiple commendations and a respected legacy within the U.S. Army Corps of Engineers.

The 521st Military Police (MP) Detachment was first constituted and activated during the post-World War II era, reflecting the growing need for military law enforcement in occupied territories and U.S. installations. Over the decades, the unit has provided crucial support in maintaining order, security, and discipline for both garrison and deployed Army units. The 521st MP Detachment has participated in various operations, including peacekeeping and support missions during conflicts such as Operation Iraqi Freedom and Operation Enduring Freedom. Renowned for its professionalism and adaptability, the detachment continues to play a vital role in supporting Army missions both at home and abroad.

The 523rd Engineer Company is a United States Army unit with a distinguished record of service in both combat and peacetime operations. Originally constituted during World War II, the company has supported a wide range of engineering missions, including construction, route clearance, and infrastructure repair. Over the decades, the 523rd has deployed to various theaters, notably providing critical support during the Vietnam War and in recent operations in Iraq and Afghanistan. Renowned for its technical expertise and adaptability, the 523rd Engineer Company continues to play a vital role in enabling Army mobility and mission success worldwide.

The 525th Quartermaster Company was first constituted during World War II to provide vital supply and logistical support to frontline units. Throughout its history, the unit has played a crucial role in ensuring the continuous flow of food, fuel, water, and equipment to combat forces during both peacetime and wartime operations. The 525th has participated in numerous campaigns, adapting to technological advances and modern supply chain methods to better serve the U.S. Army’s needs. Today, the company remains an essential element in sustaining operational readiness and supporting missions worldwide.

The 528th Military Intelligence Company (528th MI Co) was an intelligence unit within the United States Army, primarily associated with supporting airborne and special operations forces. Activated during the Cold War, the 528th MI Co provided critical intelligence, electronic warfare, and signals support to enhance the operational effectiveness of U.S. Army Special Operations Command (USASOC) units. The company played a significant role in various operations, including those in Panama, the Gulf War, and the Global War on Terrorism, delivering timely intelligence to commanders on the ground. Over time, its capabilities and mission sets evolved, and the unit was eventually reflagged as part of larger military intelligence reorganizations, contributing to the formation of the 528th Sustainment Brigade (Special Operations) (Airborne).

The 531st Maintenance Company is a support unit within the United States Army, primarily tasked with providing field and sustainment maintenance for various military equipment. Activated during the mid-20th century, the company has supported numerous operations, ensuring the readiness of vehicles and materiel for combat and logistical units. Over the decades, the 531st has deployed in support of major conflicts, including Operation Iraqi Freedom, where it played a crucial role in maintaining operational capability. Its dedicated soldiers have consistently upheld the unit’s reputation for technical proficiency and mission accomplishment.

The 537th Military Police Company was constituted on 10 June 1943 in the Army of the United States and activated on 15 June 1943 at Fort Custer, Michigan. During World War II, the unit provided critical military police support in the European Theater, including traffic control, security, and law enforcement duties. After the war, the 537th MP Company underwent several activations and inactivations, serving both stateside and overseas, including deployments in support of operations in Germany and the Middle East. The unit has a distinguished record of service, upholding military discipline and supporting combat operations across multiple conflicts.

The **537th Personnel Services Company (PSC)** was a U.S. Army unit specializing in personnel administration and human resources support. Activated during the Cold War, the 537th PSC provided critical manpower management, postal, and casualty reporting services to soldiers deployed in various theaters. Throughout its history, the unit supported major operations, including deployments during Operation Desert Storm and Operation Iraqi Freedom, ensuring seamless personnel support for combat and support units alike. The 537th PSC contributed significantly to maintaining soldier readiness and morale before being inactivated as part of Army modular restructuring in the early 21st century.

The 543 Light Truck Detachment was a logistical support unit formed during World War II to facilitate the efficient movement of troops and materiel. Assigned primarily to the European Theater, the detachment provided critical transportation services, ensuring the timely delivery of supplies to front-line units and aiding in medical evacuations. The unit was composed of skilled drivers and mechanics, operating a fleet of light trucks under often hazardous conditions. Their efforts contributed significantly to the overall mobility and effectiveness of Allied operations during key campaigns.

The 543rd Signal Company was originally constituted during World War II to provide vital communications support for U.S. Army operations in the European Theater. Activated in 1943, the unit played a key role in maintaining lines of communication during major campaigns, including the Normandy landings and the subsequent push across France. After the war, the 543rd Signal Company continued its service, adapting to evolving communications technology and supporting various operations during the Cold War era. Today, the unit remains committed to its mission of delivering reliable and secure communications for Army operations worldwide.

The 552nd Light Maintenance Company was a United States Army unit responsible for providing field-level maintenance support to combat and support units. Activated during World War II, the company played a vital role in ensuring the operational readiness of vehicles, weapons, and other essential equipment on the front lines. Throughout its service, the 552nd supported various campaigns by rapidly repairing and returning damaged equipment to action, thereby sustaining the combat effectiveness of U.S. forces. The unit's dedication exemplified the crucial behind-the-scenes work that kept frontline operations moving forward.