Joint Task Force-Southern Border (JTF-SB) 2025
Fort Huachuca, Arizona 85613
JTF-SB 2025 3/LRC/cr1/5750
CMCC NR _____3______ Ser. No. 040-25
COPY _1__ OF __10__COPIES 21 April 2025
CONFIDENTIAL
From: Commanding Officer
To: Commanding General, 1st Marine Division (Rein) FMF
Subj: Command Chronology for the period of __March 2025__
Ref: (a) MCO 5750.2
(b) FMF Pac 5750.8
(c) DivO 5750.2B
Encl: (1) Joint Task Force-Southern Border (JTF-SB) Command Chronology
1. In accordance with the above provisions of references (a), (b), and (c), enclosure (1) is submitted herewith.
JOINT TASK FORCE SOUTHERN BORDER (JTF-SB)
COMMAND CHRONOLOGY MARCH-APRIL 2025
PART I: ORGANIZATIONAL DATA
PART II: NARRATIVE SUMMARY
PART III: SEQUENTIAL LISTING OF SIGNIFICANT EVENTS
PART IV: SUPPORTING DOCUMENTS
PART I: ORGANIZATIONAL DATA
1. DESIGNATION
COMMANDER Maj. Gen. Scott M. Naumann, USA
SUBORDINATE UNITS
a.) 10th Mountain Division (Headquarters and Headquarters Battalion)
b.) 2nd Stryker Brigade Combat Team, 4th Infantry Division
c.) 101st Division Sustainment Brigade
d.) 264th Combat Sustainment Support Battalion
e.) 89th Military Police Brigade
f.) 3rd Combat Aviation Brigade
g.) 1st Combat Engineer Battalion, 1st Marine Division
a.) 10th Mountain Division (Headquarters and Headquarters Battalion)
b.) 2nd Stryker Brigade Combat Team, 4th Infantry Division
c.) 101st Division Sustainment Brigade
d.) 264th Combat Sustainment Support Battalion
e.) 89th Military Police Brigade
f.) 3rd Combat Aviation Brigade
g.) 1st Combat Engineer Battalion, 1st Marine Division
2. LOCATION
a.) HQ-Fort Huachuca, Arizona 85613
b.) Southern Border: California, Arizona, New Mexico, Texas
c.) Federally designated military installation: Roosevelt Reservation.
3. STAFF OFFICERS
Executive Officer- two deputy commanders: one from CBP and one from the U.S. Marine Corps.
Sergeant Major-
S-1/Adjutant-
S-2-
S-3-
S-4-
S-5-
Supply Officer-
Communications Officer-
Medical Officer-
M.T. Officer-
M.T. Maintenance Officer-
Engineer Equipment Officer-
Utilities Officer-
Construction Officer-
4. AVERAGE MONTHLY STRENGTH
JTF-SB commands a force of approximately 10,000 service members, including units from the Army, Marine Corps, National Guard, and Reserve components
OFF- in progress
ENL- in progress 5. CASUALTY REPORT
15 April 2025:
(Non-combat related death, vehicle accident, Santa Teresa, NM) Lance Cpl. Albert A. Aguilera, 22, of Riverside, California, was a combat engineer with 1st Combat Engineer Battalion, 1st Marine Division.
(Non-combat related death, vehicle accident, Santa Teresa, NM) Lance Cpl. Marcelino M. Gamino, 28, of Fresno, California, was a combat engineer with 1st Combat Engineer Battalion, 1st Marine Division.
(Non-combat related injury, vehicle accident, Santa Teresa, NM) USMC, Enlisted, unidentified.
PART II: NARRATIVE SUMMARY
Joint Task Force-Southern Border (JTF-SB) is a newly established military command under U.S. Northern Command (USNORTHCOM), activated in March 2025 at Fort Huachuca, Arizona. Its primary mission is to synchronize Department of Defense (DoD) efforts to secure and seal the U.S. southern border, supporting the Department of Homeland Security (DHS) and U.S. Customs and Border Protection (CBP) in maintaining operational control and territorial integrity from San Diego, California, to McAllen, Texas.
JTF-SB is tasked with executing full-scale, agile, and multi-domain operations to prevent illegal activity and secure the border, enhancing the efficiency and effectiveness of DoD support to DHS and CBP
Tactical Area of Responsibility (TAOR) for each subordinate unit will be addressed in subsequent updated command chronologies,
PART III:
SEQUENTIAL LISTING OF SIGNIFICANT EVENTS
February 2025, Headquarters and Headquarters Battalion, 10th Mountain Division (Light Infantry) from Fort Drum, New York, deployed to Fort Huachuca to set up the infrastructure for the new task force.
March 2025: About 500 members from the 10th Mountain Division arrived at Fort Huachuca to form the JTF-SB headquarters
March 2025: Approximately 10,000 service members were either deployed or scheduled to deploy under JTF-SB, including units from the Army, Marine Corps, and Air Force 01 March 2025: A Stryker brigade combat team and a general support aviation battalion were deployed to reinforce border operations, prior to the formal activation of JTF-SB
14 March 2025: JTF-SB officially assumed command and control of the southern border mission from Joint Task Force-North (JTF-N)
14 March 2025: JTF-SB began overseeing operations along the entire U.S. southern border, from San Diego, California, to McAllen, Texas.
Mid-April 2025, JTF-SB was actively conducting patrols and operations along the border.
PART IV: SUPPORTING DOCUMENTS
1. EQUIPMENT AND LOGISTICS
a.) COMMUNICATIONS
1) All-Domain Communications: JTF-SB is expected to utilize a robust, multi-layered communications infrastructure supporting air, land, maritime, and cyber domains. This would include secure voice, data, and video communications to coordinate operations across multiple service branches and agencies
2) Tactical Satellite (TACSAT) and Mobile User Objective System (MUOS): Drawing from the communications approach of other USNORTHCOM joint task forces, such as JTF-Civil Support, JTF-SB likely employs tactical satellite communications. The MUOS system provides secure, resilient, and immediate communications capabilities, even in austere or infrastructure-denied environments. This system allows for global connectivity, with radios functioning similarly to cell phones and capable of connecting to the Defense Switched Network (DSN)
3) Interoperability: Communications systems are designed for interoperability among all U.S. military branches and with key federal, state, and local agencies. This ensures seamless information sharing and rapid coordination during operations.
4) Communications Security (COMSEC): Strong emphasis on encryption and secure handling of communications, including the management of cryptographic keys and secure satellite access protocols, to prevent interception or compromise of sensitive information
5) Redundancy and Resilience: The communications architecture is built to withstand disruptions—whether from physical attacks, cyber threats, or natural disasters—by incorporating redundant pathways and rapid reconstitution capabilities
6) Mobile and Deployable Assets: JTF-SB likely fields mobile communications platforms, such as deployable command posts and vehicle-mounted systems, to maintain connectivity during dynamic border operations.
1) All-Domain Communications: JTF-SB is expected to utilize a robust, multi-layered communications infrastructure supporting air, land, maritime, and cyber domains. This would include secure voice, data, and video communications to coordinate operations across multiple service branches and agencies
2) Tactical Satellite (TACSAT) and Mobile User Objective System (MUOS): Drawing from the communications approach of other USNORTHCOM joint task forces, such as JTF-Civil Support, JTF-SB likely employs tactical satellite communications. The MUOS system provides secure, resilient, and immediate communications capabilities, even in austere or infrastructure-denied environments. This system allows for global connectivity, with radios functioning similarly to cell phones and capable of connecting to the Defense Switched Network (DSN)
3) Interoperability: Communications systems are designed for interoperability among all U.S. military branches and with key federal, state, and local agencies. This ensures seamless information sharing and rapid coordination during operations.
4) Communications Security (COMSEC): Strong emphasis on encryption and secure handling of communications, including the management of cryptographic keys and secure satellite access protocols, to prevent interception or compromise of sensitive information
5) Redundancy and Resilience: The communications architecture is built to withstand disruptions—whether from physical attacks, cyber threats, or natural disasters—by incorporating redundant pathways and rapid reconstitution capabilities
6) Mobile and Deployable Assets: JTF-SB likely fields mobile communications platforms, such as deployable command posts and vehicle-mounted systems, to maintain connectivity during dynamic border operations.
b. LOGISTICS
1) Joint Task Force Southern Guard (JTF-SG), sometimes referenced as JTF-SB, operates with a robust and integrated logistics structure that is essential to its mission success. The logistics section, known as J4, is the backbone of the task force, ensuring continuous support for personnel, equipment, and operations, particularly in dynamic and high-tempo environments such as migrant operations at Naval Station Guantanamo Bay.
2) Organizational Structure JTF-SG J4 is a fully integrated joint logistics cell. Representatives come from U.S. Army South (USARSOUTH), U.S. Naval Forces Southern Command/U.S. Fourth Fleet (USNAVSOUTH/FOURTHFLT), U.S. Air Force Southern Command (AFSOUTH), and include a civilian logistics representative. The cell operates in close coordination with the Operational 3) Contract Support Integration Cell (OCSIC), which oversees all contracted logistics support, including food, fuel, maintenance, and base life support services.
Key Functions Strategic Mobility & Transportation: Oversees all aspects of strategic transportation, including air, sea, and ground movement of personnel, cargo, and equipment. Responsible for tracking force flow, ensuring timely arrivals, and managing joint reception, staging, onward movement, and integration.
Supply & Sustainment: Manages the distribution of fuel, rations, water, and equipment. Ensures accurate forecasting and inventory management to sustain operations.
4) Contract Management: OCSIC integrates contracting activities across all service branches, ensuring alignment with mission requirements and fiscal responsibility.
5) Planning & Operations: J4 is divided into Current Operations (CUOPS) for daily sustainment and Future Operations (FUOPS) for long-term planning. Maintains multiple contingency plans to adapt to changing mission requirements.
6) Accountability: Strict management of inventory and property accountability, including reconciliation and return processes for all issued supplies.
7) Integration and Coordination J4 logisticians are embedded across the task force, building relationships with partner agencies and ensuring seamless support. The joint nature of the cell allows for rapid adaptation to evolving mission demands and maximizes the use of available resources. Coordination with the joint logistics element ensures that all operational units are fully equipped, sustained, and mission-ready
c. CLOSE AIR SUPPORT/DECONFLICTION
2) Organizational Structure JTF-SG J4 is a fully integrated joint logistics cell. Representatives come from U.S. Army South (USARSOUTH), U.S. Naval Forces Southern Command/U.S. Fourth Fleet (USNAVSOUTH/FOURTHFLT), U.S. Air Force Southern Command (AFSOUTH), and include a civilian logistics representative. The cell operates in close coordination with the Operational 3) Contract Support Integration Cell (OCSIC), which oversees all contracted logistics support, including food, fuel, maintenance, and base life support services.
Key Functions Strategic Mobility & Transportation: Oversees all aspects of strategic transportation, including air, sea, and ground movement of personnel, cargo, and equipment. Responsible for tracking force flow, ensuring timely arrivals, and managing joint reception, staging, onward movement, and integration.
Supply & Sustainment: Manages the distribution of fuel, rations, water, and equipment. Ensures accurate forecasting and inventory management to sustain operations.
4) Contract Management: OCSIC integrates contracting activities across all service branches, ensuring alignment with mission requirements and fiscal responsibility.
5) Planning & Operations: J4 is divided into Current Operations (CUOPS) for daily sustainment and Future Operations (FUOPS) for long-term planning. Maintains multiple contingency plans to adapt to changing mission requirements.
6) Accountability: Strict management of inventory and property accountability, including reconciliation and return processes for all issued supplies.
7) Integration and Coordination J4 logisticians are embedded across the task force, building relationships with partner agencies and ensuring seamless support. The joint nature of the cell allows for rapid adaptation to evolving mission demands and maximizes the use of available resources. Coordination with the joint logistics element ensures that all operational units are fully equipped, sustained, and mission-ready
1)
JTF-SB (Joint Task Force–Southern Border) is a newly established U.S. military joint task force under USNORTHCOM, created to coordinate efforts along the southern border, focusing on sealing the border and repelling illegal activity.
2) There is no direct evidence in the search results that JTF-SB is currently conducting or has conducted close air support (CAS) missions. However, understanding the role of CAS in joint task force operations and the general doctrine is important for context.
3) Key Elements of CAS: Integration: Requires detailed planning and coordination between air and ground forces.
JTACs: Joint Terminal Attack Controllers (JTACs) are specially trained personnel who direct CAS missions and ensure the safety of friendly forces
4) Aircraft: While many aircraft can perform CAS, the A-10 Thunderbolt II is specifically designed for this mission.
5) Procedures: Missions use a strict checklist called the "9 line" to ensure accuracy and minimize the risk of friendly fire
6) CAS in Joint Task Forces Joint task forces, such as JTF-SB, operate under joint doctrine that includes the potential for CAS missions when needed. The doctrine (JP 3-09.3) outlines that CAS is planned and executed to support ground tactical units, with the ground commander responsible for the employment of CAS assets within their operational area
7) CAS can be used in a variety of environmental conditions and is often integrated with other supporting fires to achieve mission objectives
h.) Applicability to JTF-SB While there is no public documentation specifically linking JTF-SB to current CAS operations, the task force would follow established joint doctrine for CAS if the operational environment required it. This would involve: Detailed planning and coordination with ground and air components.
Use of JTACs to direct airstrikes in support of border security operations if hostile threats required such measures.
Integration of CAS into the broader concept of operations as determined by the ground commander.
2) There is no direct evidence in the search results that JTF-SB is currently conducting or has conducted close air support (CAS) missions. However, understanding the role of CAS in joint task force operations and the general doctrine is important for context.
3) Key Elements of CAS: Integration: Requires detailed planning and coordination between air and ground forces.
JTACs: Joint Terminal Attack Controllers (JTACs) are specially trained personnel who direct CAS missions and ensure the safety of friendly forces
4) Aircraft: While many aircraft can perform CAS, the A-10 Thunderbolt II is specifically designed for this mission.
5) Procedures: Missions use a strict checklist called the "9 line" to ensure accuracy and minimize the risk of friendly fire
6) CAS in Joint Task Forces Joint task forces, such as JTF-SB, operate under joint doctrine that includes the potential for CAS missions when needed. The doctrine (JP 3-09.3) outlines that CAS is planned and executed to support ground tactical units, with the ground commander responsible for the employment of CAS assets within their operational area
7) CAS can be used in a variety of environmental conditions and is often integrated with other supporting fires to achieve mission objectives
h.) Applicability to JTF-SB While there is no public documentation specifically linking JTF-SB to current CAS operations, the task force would follow established joint doctrine for CAS if the operational environment required it. This would involve: Detailed planning and coordination with ground and air components.
Use of JTACs to direct airstrikes in support of border security operations if hostile threats required such measures.
Integration of CAS into the broader concept of operations as determined by the ground commander.
2. AFTER ACTION REPORT-TASK FORCE SAPPER
a.) Task Force Sapper is a military unit composed primarily of U.S. Marines and Sailors, notably from the I Marine Expeditionary Force. As of 2025, the task force consists of approximately 500 personnel who have been assigned to support operations along the U.S. southern border.
1) Mission and Activities: Task Force Sapper has been tasked with providing logistics and engineering support as part of the broader Southern Border Mission.
Their activities include reinforcing border barriers by deploying concertina wire and other fortifications near locations such as San Ysidro and Otay Mesa, California.
These operations are conducted under the direction of U.S. Northern Command and as part of Joint Task Force–Southern Border, which coordinates all-domain operations to enhance border security and deter illegal activity.
2) Sapper Role in the Military: The term "sapper" refers to elite combat engineers skilled in a variety of military engineering duties, including minefield placement and clearing, construction of tactical support structures, demolition, and more. Sappers are recognized for their expertise in mobility, counter-mobility, and survivability tasks, making them critical to both offensive and defensive military operations
In March and April 2025, Task Force Sapper has been actively involved in reinforcing the southern border by installing concertina wire and supporting infrastructure improvements. Their efforts are part of a larger, agile response to evolving border security challenges, providing both physical barriers and rapid engineering solutions.
Image: OTAY MESA, CALIFORNIA, UNITED STATES/03.07.2025/
Lance Cpl. Nataly Espi USMC.
b.) Otay Mesa border wall
The Otay Mesa border wall refers to a significant section of the United States–Mexico border barrier located in the Otay Mesa area of San Diego, California. This stretch is part of what is colloquially called the "Tortilla Wall," a 14-mile (22.5 km) segment running from the Otay Mesa border crossing to the Pacific Ocean1. The wall was originally completed in the early 1990s and is the longest continuous border wall section in the region.
The wall near Otay Mesa consists of both a primary and a secondary fence.
The secondary fence is approximately 30 feet tall and constructed of vertical metal bollards
The area is heavily monitored and patrolled, with frequent use of surveillance and rapid response by U.S. Border Patrol agents.
| Feature | Description |
|---|---|
| Location | Otay Mesa, San Diego, CA to Pacific Ocean |
| Length | 14 miles (Tortilla Wall section) |
| Height | ~30 feet (secondary fence) |
| Construction | Vertical metal bollards, electrical conduit on top |
| Key Incidents | Fatal falls, rescues of stuck individuals |
| Effectiveness | Major drop in apprehensions post-construction |
| Criticism | Shifts crossings to more dangerous areas; symbolic debate |
| Recent Developments | New port of entry construction, prototype wall testing |
Conclusion
The Otay Mesa border wall is a prominent and heavily fortified section of the U.S.–Mexico border, designed to deter illegal crossings but also associated with significant risks for migrants. It remains a focal point for border security operations, humanitarian concerns, and cross-border economic activity.
https://www.perplexity.ai/search/otay-mesa-border-wall-8zQ1LC.wR6SFbjShsTVvzg
End of After Action Report
End JTF-SB Command Chronology, March-April 2025
Report prepared by: JC L'Angelle, Pvt., USMC,
MOS 2533 Communications (212xxxx)
H&S Co., 27th Marines Combat Regt., Tet '68.
(Image: Tiltrotor, https://rumble.com/v2db90y-u.s.-marines-with-marine-medium-tiltrotor-squadron-complete-service-level-t.html)