History of the 31st Engineer Battalion

History of the 31st Engineer Battalion (Combat) (Army)

The 31st Engineer Battalion was first organized 1 July 1940 at Fort Belvoir, Virginia as the 31st Engineer Company (Combat). Effective 15 December 1941, the 31st Engineer Company (Cbt) was reorganized, expanded and redesignated as the 31st Engineer Combat Battalion. On 29 April 1942, the battalion was reorganized, expanded and redesignated the 31st Engineer Combat Regiment. Less than a year later, on 22 March 1943, the regiment was divided — the Headquarters Company became Headquarters, 1114th Engineer Combat Group, and its 1st and 2nd Battalions became the 31st Engineer Combat Battalion and the 241st Engineer Combat Battalion, respectively.

The 31st Engineer Combat Battalion departed New York Port of Embarkation 22 October 1944 for overseas service during World War II, arriving in England 2 November 1944, then to France 31 December 1944 where it bulldozed its way through western Europe with the Seventh U.S. Army and was inserted into the Bouxwiller area (north of Strasbourg, east of Nancy) in the French Alsace region, to construct defenses against a possible renewed German attack. Company B was detached to provide direct support of the 36th Infantry Division’s continuing advance into Germany.

Names like Maginot Line, the Siegfried Line, Rhine River and Mannheim were all too familiar to the men of the battalion, as they spent a long, cold winter blasting captured bunkers, building bridges and clearing both land mines and “secured” areas. Shortly after V-E Day, the 31st arrived in Vienna, Austria, where the men enjoyed several well-deserved, restful months. In small groups the men of the 31st rotated home until the last contingent arrived at the New York Port of Embarkation on 7 March 1946. The battalion was inactivated two days later at Camp Kilmer, New Jersey.

The 31st was re-activated at Camp McCoy, Wisconsin 10 March 1951, during the Korean War. On 8 Jun 1953 the battalion was reorganized and redesignated the 31st Engineer Battalion and moved to Fort Carson, Colorado, where on 15 December 1956, it was again inactivated.

The 31st was again activated at Fort Chaffee, Arkansas on 17 June 1963 to be immediately involved in construction of a 120 foot Bailey Bridge across Arkansas State Highway 25 in conjunction with President Kennedy’s dedication of Greer’s Ferry Dam. One week later, the tired men of the 31st answered an emergency call from Heavener, Oklahoma where a raging forest fire was threatening a number of towns – more than 4000 acres were blackened by the blaze by the time the 31st arrived. After 72 hours of steady work, the fire was brought under control. Both actions brought commendations to the battalion.

In October 1964, the 31st Engineer Battalion was reassigned to Fort Bliss, Texas where it continued to provide broad engineer support to the area. As engineer requirements of the Vietnam War increased, the 31st was moved to Dona Anna Range, New Mexico for training, staging, and preparation for overseas movement to Vietnam. The battalion experienced several “false starts” each beginning with a serious build-up of personnel, equipment, and training for deployment in the Vietnam theater, but with each build-up, just prior to deployment, the plans were changed and instead of moving as a unit, its soldiers were dispatched to Vietnam as individual replacements. The penultimate iteration involved filling the battalion with Air Defense soldiers to be trained as combat engineers, but the men primarily spent their days performing post details. That plan was also set aside and the Air Defense soldiers were returned to Air Defense units. In early 1967, Army-trained combat engineers again began arriving to fill the 31st; concurrently, required TOE equipment began arriving, appropriate individual and unit training was undertaken. Soldiers who were unqualified for duty in a hostile environment were reassigned to other units and priority replacements came pouring in to be trained up to deployment standard. Vehicles and other equipment were brought to high status of maintenance.

In early 1968, the unit was declared combat ready and cleared for overseas movement. The battalion’s equipment was delivered by rail to Beaumont, Texas for transport to Vietnam aboard cargo ships and the soldiers were given a short leave to visit and say farewell to family and loved ones. Finally, on 4 April 1968, the 31st Combat Engineer Battalion’s main body departed Fort Bliss, TX by plane to Oakland, CA, thence 22 days by sea aboard the MTST transport ship USNS Barrett; concurrently a small advance party departed by air, flying directly to Saigon. After 22 days at sea, with one stop for water and fuel in Naha, Okinawa, the Barrett arrived at Vung Tau, Vietnam where the men were transported close to the beach aboard US Navy landing barges, then waded ashore. The men were then flown by USAF C-130s to Blackhorse Base Camp near Xuan Loc where they began providing engineer support to the 11th Armored Cavalry Regiment and for III CTZ Airmobile units.

The names Blackhorse, Camp Castle, Bearcat, Ben Tre, La Nga River, Phan Thiet, Xuan Loc, Hill 837, Bien Hoa, Song Be, Quan Loi, Katum, and Phouc Vinh became more than projects and bases to the men of the 31st as their efforts transformed the face of South Vietnam.

Shortly after arrival at Blackhorse Base Camp, Company B of the 31st was deployed to Bearcat Base Camp with the mission of constructing the Royal Thai Regiment’s Cantonment MER (1 May 68 to 31 Aug 68). Though faced with periodic problems of material shortages and changes in scopes of work, Company B’s engineers continued dedicated work on the MER eventually constructing 334 WABTOC structures for our allies.

A platoon-sized element of Company A was deployed and assigned the significant project of constructing a 2800 foot runway (with turn-arounds) at Ben Tre, Vietnam, in a remote area of the Mekong Delta, south of My Tho. Again, interruption of logistical support would interrupt normal operations, nevertheless, the platoon successfully accomplished its mission.

Operation McClain implemented in early August 1968, was the basis for C Company being deployed to Phan Thiet on the China Sea, in support of the 506th Airborne Infantry Battalion, 101st Airborne Division. During that operation, the men of Company C constructed divisional fire support bases, repaired and maintained interdicted Lines of Communication, and repaired and maintained airfields, all enhancing effective operations of the supported unit. .

At Blackhorse Base Camp in direct support of the 11th Armored Cavalry Regiment, Company D immediately undertook base camp development, including grease racks for 21 units, concrete pads for 130 one- and two-story billets, a 1400 square foot Special Services facility (Service Club) and continuing construction and maintenance of roads and drainage. These efforts were temporarily interrupted 22 Jun to 5 Jul 68, when Company D was rapidly deployed to support reconstruction of the interdicted La Nga River/QL 20 Float Bridge, its bypass and crossing. Company D’s prompt reaction led to successful reconstruction of the bridge and rapid reopening of the highway, after which they returned to Blackhorse Base Camp to complete the base camp development projects.

Additionally at Blackhorse, the 31st constructed howitzer gun pads for the 7th Battalion, 8th Field Artillery, a bypass for the 54th Field Artillery Group, a drainage facility for the MACV Compound in nearby Xuan Loc; installed a water system on Hill 837 (Nui Chun Chan) for the Signal Relay Station there, participated in nightly ambush patrols with the 11th ACR, and conducted extensive minefield clearing projects at Bien Hoa AF Base for the 101st Airborne Division and the USAF Red Horse Civil Engineer Squadron.

The standard tour of duty in Vietnam was twelve months. Shortly after the battalion’s arrival, men of the 31st learned of an in-country policy called “Infusion,” which was designed to redistribute soldiers’ departure dates to preclude large numbers of key personnel leaving at the same time. Under “Infusion” the battalion was required to select a large number of its trained, experienced personnel of all ranks for reassignment to other units and in-turn, the 31st would receive well-qualified replacements with varying departure dates, from other in-country units. The 31st implemented the directive, which brought seriously negative impacts on both those being reassigned out and in. Nevertheless, the battalion adjusted as did the men, and went on to continue to perform at a high level of excellence.

Duty requirements in the 31st were typically twelve hours a day, seven days a week, with time off for chow and on Sunday, for church services. Using the battalion’s unit fund projectors and a large sheet stretched between two telephone poles, movies obtained from the USO and USA Special Services were shown nearly every night on the battalion parade field. After hours clubs were set up using GP medium tents secured to wooden frames for use by the soldiers of the battalion. Letters were sent to beverage and snack companies in the United States soliciting anything they could spare to help make our situation a little more like home – when their gifts arrived, they were divided evenly between the battalion’s three soldier-built clubs, to make them more like clubs at home and to help build the men’s morale. Additionally, a five-day Rest & Recuperation leave was authorized to various locations in the Pacific theater of operation for each soldier after completing six months in-country.

Another popular morale-enhancing project was the states’ flags. The state flags were requested and received from the states’ governors, then flown on flagstaffs installed along the walkway to the main entrance of the Battalion Headquarters. Periodically, a state flag day would be announced and soldiers from across the battalion were invited to the HQ to have their photograph taken holding their state flag with the Battalion Commander; then the state’s contingent would join together to raise the flag up the main flag staff for the remainder of the day. Photos of all this were taken and sent back to the states, along with individual Home Town News Releases. These news releases and photographs, when published by the hometown newspapers, resulted in many pleased and proud soldiers, parents, residents of the soldiers’ home town and governors.

Continuing to show ingenuity, soldiers of the 31st began publishing its own newspaper named “The Black Spade” (taken from the battalion’s distinctive unit insignia, commonly known as the crest). This undertaking, led by volunteers from the personnel section with reporters from each company, was a major morale-building undertaking and remained popular throughout the following year.

Under Operation Liberty Canyon, the 31st was ordered in November 1968 to deploy to Phouc Vinh, Vietnam to prepare that former French base camp for occupation and use by the 1st Air Cavalry Division. The 31st promptly reacted to the requirement, subsequently building fortifications and obstacles surrounding the base camp, several hundred revetments for the division’s fixed and rotary wing aircraft, completely reshaping, compacting, and laying pierced steel planking on the base’s airfield, and constructing troop quarters. All battalion elements were involved in these projects and both assigned and assumed missions were promptly completed, drawing high praise from the CG, 1stAir Cavalry Division.

For their valorous, meritorious and selfless contributions during the first year of Vietnam service, a large number of the battalion’s men were decorated with appropriate individual awards and for its exceptional service and meritorious contributions, the battalion itself was awarded the USA Meritorious Unit Commendation Streamer, embroidered “VIETNAM 1968”, for the period May – Dec 1968, and the RVN Civic Actions Honor Medal First Class, embroidered “VIETNAM 1968-1970”.

Additional comments re Co B role in Cambodia Incursion, May 1970 (published in VIETNAM magazine, August 2005 edition).

Submitted by John Lough:
“In honor of all those Engineers who served and supported the Cambodian mission from headquarters to the front line:
The Cambodian Incursion in May and June 1970 was one of the largest combat operations of the Vietnam War. President Nixon sent 32,000 soldiers, including engineers of the 20th Brigade. Twenty six men of Company C 31st Combat Engineer Battalion became the first engineers to reach Cambodian soil on May 5th.  A bridge destroyed by a stunned and retreating enemy kept the 11th Armored Cav. from encircling the enemy sanctuary. After combat assaulting with the 11th ACR into the dense jungle, they were able to clear the mangled bridge away.While the road to Memot was inching its way forward, other engineers including Charlie Company were building their way to Snoul chasing the NVA back toward their headquarters. Then the word was received that “The City” had been found. Company C 31st Engineer Bn and 557th Engineers were dispatched to begin ripping a trail while under enemy fire to “The City” and “Rock Island East” then began removing tons and tons of NVA supplies, destroying what was left. Many Engineers were killed or wounded during this operation. For their action, Charlie Company 31st Combat Engineers was awarded a Citation for Valor.”

See original blog post with images.

After nearly 4 years of service in Vietnam, the battalion returned to Fort Lewis, Washington, where it was inactivated 12 March 1972.

Effective 30 September 1986, the Headquarters and Headquarters Company was assigned to the United States Training and Doctrine Command (TRADOC) and activated at Fort Leonard Wood, Missouri. The battalion was subsequently inactivated and re-activated several times from October 1993 to 2 August 2007, when it was once again returned to active duty status at Fort Leonard Wood, MO, where it is currently stationed, training today’s US Army combat engineers.


World War I


World War II

Ardennes-Alsace Counteroffensive

Rhineland Counteroffensive, Phase IV

Central Europe Counteroffensive, Phase V

Counteroffensive, Phase VI



VN Counteroffensive IV

VN Counteroffensive Phase V

VN Counteroffensive Phase VI

Tet 69 Counteroffensive

Summer-Fall 1969

Winter-Spring 1970

Sanctuary Counteroffensive

Counteroffensive, Phase VII

Consolidation I

Consolidation II


Meritorious Unit Commendation, Streamer embroidered VIETNAM 1968

(May-Dec 1968: DAGO 39- 1970)

Civil Actions Honor Medal first Class, Streamer embroidered VIETMAN 1968-1970

(Apr 1968-Feb 1970: DAGO 43- 1970)

Republic of Vietnam Cross of Gallantry with Palm, Streamer embroidered VIETNAM 1970 (awarded to Co C, 31st Engr Bn; May-Jun 1970: DAGO 55- 1971)

Valorous Unit Award, Streamer embroidered FISH HOOK

(May-June 1970: DAGO 43- 1972)

1 An anonymous historical summary of the 31st Engineer Battalion suggests the battalion was active and participated in American Expeditionary Forces’ campaigns in Europe during World War I; however, the referenced service has not been verified.