Operation Iron Mountain was a two-year security and "search and clear" operation during the Vietnam War, involving U.S., South Vietnamese, and provincial forces. Conducted from February 1969 to February 1971, it targeted the enemy's main force and local units, as well as their supply and communication lines, in Quảng Ngãi Province, South Vietnam.
Key aspects of Operation Iron Mountain
• Objective: To find and destroy enemy forces, bases, and supply routes, and deny them access to populated areas, especially those near the Central Highlands.
• Location: Southeastern Quảng Ngãi Province, a region occupied by North Vietnamese forces in the later years of the war.
• Units involved: The primary U.S. force was the 11th Light Infantry Brigade of the Americal Division. They conducted combined operations with Army of the Republic of Vietnam (ARVN) and provincial forces.
• Tactics: U.S. and allied units used saturation patrols, ambushes, and combat air assaults. The operation also involved "rice denial" programs and civic action projects, such as building schools and clinics, to support the pacification effort.
• Casualties and outcome: The operation concluded on February 28, 1971.
o US forces: 440 killed.
o Enemy forces: US estimates claimed 4,589 enemy killed and 137 captured.
o Result: The operation was considered a US "operational success".
Fire Support Base (FSB) Hill 4-11 was a vital base of operations for the 11th Light Infantry Brigade (Americal Division) during Operation Iron Mountain. The firebase was established in July 1969 to support search-and-clear operations against North Vietnamese Army (NVA) and Viet Cong (VC) forces in the Quang Ngai Valley.
Key aspects of Operation Iron Mountain
• Objective: To find and destroy enemy forces, bases, and supply routes, and deny them access to populated areas, especially those near the Central Highlands.
• Location: Southeastern Quảng Ngãi Province, a region occupied by North Vietnamese forces in the later years of the war.
• Units involved: The primary U.S. force was the 11th Light Infantry Brigade of the Americal Division. They conducted combined operations with Army of the Republic of Vietnam (ARVN) and provincial forces.
• Tactics: U.S. and allied units used saturation patrols, ambushes, and combat air assaults. The operation also involved "rice denial" programs and civic action projects, such as building schools and clinics, to support the pacification effort.
• Casualties and outcome: The operation concluded on February 28, 1971.
o US forces: 440 killed.
o Enemy forces: US estimates claimed 4,589 enemy killed and 137 captured.
o Result: The operation was considered a US "operational success".
Fire Support Base (FSB) Hill 4-11 was a vital base of operations for the 11th Light Infantry Brigade (Americal Division) during Operation Iron Mountain. The firebase was established in July 1969 to support search-and-clear operations against North Vietnamese Army (NVA) and Viet Cong (VC) forces in the Quang Ngai Valley.
FSB Hill 4-11
Establishment of FSB Hill 4-11
• Command decision: In July 1969, Lieutenant Colonel George Ellis, commander of the 3rd Battalion, 1st Infantry, was ordered to choose a site for a new firebase in the Quang Ngai Valley.
• Strategic location: The location chosen for FSB Hill 4-11 provided a commanding view of the surrounding valley. Previous U.S. positions in the area had been abandoned after sustaining heavy casualties from NVA and VC forces, and this new location was intended to offer better protection.
• Intense fighting: The area was a major infiltration route for four NVA battalions. Following its establishment, the firebase endured weeks of fierce fighting before earning its security.
Function and activities
• Operational hub: FSB Hill 4-11 served as a hub for the 3rd Battalion, 1st Infantry and other 11th LIB units during Operation Iron Mountain. The firebase supported the infantry with 4.2-inch mortar platoons and artillery to allow companies to conduct saturation patrols and ambushes in the surrounding area.
• Logistical support: The base provided essential logistical support, including stockpiled rations, water, and medical supplies, to sustain troops in the field.
• Humanitarian aid: The base also played a role in pacification efforts. Following floods in October 1969, thousands of refugees sought shelter near FSB Hill 4-11. U.S. and South Vietnamese forces created Tu My Village to accommodate these displaced civilians, providing them with security, food, and medical treatment.
• Ongoing security: Even as U.S. involvement began to wind down in late 1970, the 11th LIB continued to operate from FSB Hill 4-11, conducting continuous patrols to shield the local population from enemy attacks and harassment.
• Command decision: In July 1969, Lieutenant Colonel George Ellis, commander of the 3rd Battalion, 1st Infantry, was ordered to choose a site for a new firebase in the Quang Ngai Valley.
• Strategic location: The location chosen for FSB Hill 4-11 provided a commanding view of the surrounding valley. Previous U.S. positions in the area had been abandoned after sustaining heavy casualties from NVA and VC forces, and this new location was intended to offer better protection.
• Intense fighting: The area was a major infiltration route for four NVA battalions. Following its establishment, the firebase endured weeks of fierce fighting before earning its security.
Function and activities
• Operational hub: FSB Hill 4-11 served as a hub for the 3rd Battalion, 1st Infantry and other 11th LIB units during Operation Iron Mountain. The firebase supported the infantry with 4.2-inch mortar platoons and artillery to allow companies to conduct saturation patrols and ambushes in the surrounding area.
• Logistical support: The base provided essential logistical support, including stockpiled rations, water, and medical supplies, to sustain troops in the field.
• Humanitarian aid: The base also played a role in pacification efforts. Following floods in October 1969, thousands of refugees sought shelter near FSB Hill 4-11. U.S. and South Vietnamese forces created Tu My Village to accommodate these displaced civilians, providing them with security, food, and medical treatment.
• Ongoing security: Even as U.S. involvement began to wind down in late 1970, the 11th LIB continued to operate from FSB Hill 4-11, conducting continuous patrols to shield the local population from enemy attacks and harassment.
Tu My Village
Several combat engagements occurred in and around Fire Support Base (FSB) Hill 4-11 during Operation Iron Mountain, pitting the U.S. 3rd Battalion, 1st Infantry Regiment against persistent Viet Cong (VC) and North Vietnamese Army (NVA) forces. Due to the nature of guerrilla warfare and the enemy's use of booby traps and snipers, the fighting often consisted of small-scale ambushes and sporadic attacks rather than large, direct assaults.
Early phase: establishing the perimeter (July 1969)
Initial deployment: In July 1969, elements of the 3rd Battalion, 1st Infantry Regiment arrived to establish FSB Hill 4-11. The site, located west of Quang Ngai City, had previously been used by U.S. forces before being abandoned due to heavy casualties.
Early phase: establishing the perimeter (July 1969)
Initial deployment: In July 1969, elements of the 3rd Battalion, 1st Infantry Regiment arrived to establish FSB Hill 4-11. The site, located west of Quang Ngai City, had previously been used by U.S. forces before being abandoned due to heavy casualties.
Quang Ngai City
• Persistent resistance: From the very beginning, U.S. troops faced skilled VC snipers who knew the terrain well. They would disguise themselves as farmers, set up rifles in hidden locations, and fire at American soldiers before disappearing.
• Booby trap and sniper threat: The most significant threat came from expertly placed booby traps and snipers. This forced the soldiers to constantly be on high alert, even when unloading gear or establishing a perimeter. The relentless, unpredictable violence from these attacks took a heavy physical and emotional toll on the troops.
• Heavy fighting: The surrounding area was a major infiltration route used by four NVA battalions. The new base endured weeks of fierce fighting before the perimeter was secured.
Small unit engagements
• Search and ambush tactics: Units conducting patrols around the firebase frequently made contact with small, scattered enemy forces. This included both day and night ambushes, often supported by artillery fire from the firebase.
• Guerrilla attrition: The constant low-level combat, rather than a single large battle, characterized the fighting. • Enemy forces rarely caused heavy casualties at once but consistently harassed American troops with small-arms fire and booby traps, wearing down morale and causing steady losses.
• Booby trap and sniper threat: The most significant threat came from expertly placed booby traps and snipers. This forced the soldiers to constantly be on high alert, even when unloading gear or establishing a perimeter. The relentless, unpredictable violence from these attacks took a heavy physical and emotional toll on the troops.
• Heavy fighting: The surrounding area was a major infiltration route used by four NVA battalions. The new base endured weeks of fierce fighting before the perimeter was secured.
Small unit engagements
• Search and ambush tactics: Units conducting patrols around the firebase frequently made contact with small, scattered enemy forces. This included both day and night ambushes, often supported by artillery fire from the firebase.
• Guerrilla attrition: The constant low-level combat, rather than a single large battle, characterized the fighting. • Enemy forces rarely caused heavy casualties at once but consistently harassed American troops with small-arms fire and booby traps, wearing down morale and causing steady losses.