The unit performed operations throughout France in support of the American Expeditionary Forces of General "Blackjack" Pershing. The Regiment constructed buildings, hospitals and reconstructed railroads. On 18 October 1918, the Regiment was broken up and its elements reorganized as follows:
Headquarters disbanded,
"A" Company redesignated as 42nd Company, 20th Engineers,
"B" Company redesignated as 43rd Company, 20th Engineers,
"C" Company redesignated as 44th Company, 20th Engineers,
"D" Company redesignated as 45th Company, 20th Engineers.

Following the Armistice, the unit returned to the United States and in June/July 1919, the 42nd, 43rd, 44th and 45th Companies, 20th Engineers were demobilized at Camp Merritt, New Jersey and Newport News, Virginia.

WW II, The Engineers' War

01 October 1933 the unit was reconstituted in the Regular Army as the 42nd Engineers and on 01 June 1940, activated at Fort Benning, Georgia. During 1941, the unit grew to full strength and as part of their training took part in the Louisiana Maneuvers. After completion of its combat training, the unit helped in the construction of Camp Shelby, Mississippi and Camp Beauregard, Louisiana.

On 01 August 1942, the unit was redesignated as the 20th Engineer Combat Regiment. Preparations for their overseas assignment began immediately. On 01 November 1942, they boarded the USAT "Cristobal", a converted banana boat from Central America. They were not told of their destination, Casablanca, French North Africa, until after sea a couple of days. Landing on 19 November, as reported by one member "we emerged from the bowels of the good ship, loaded down with full field packs, gas masks and arms and carrying on our backs the largest and heaviest barracks bags that ever made an invasion". Once on the dock, in formation and with the band playing, they marched through the streets of Casablanca amid the astonished citizens.

Stationed temporarily at Piscine, then moving on to the Hippodrome, outside of Casablanca, the units first assignment was to assist in unloading all the cargo for the African operations. In January 1943, they were relieved of their cargo handling duties by a regular Port Battalion. Their next assignment was the clearing and fortification of the hotel site (Hotel D'Anfa) for the now famous Casablanca Conference where President Roosevelt and Prime Minister Churchill met with the French and Russian representatives to map out the Allied Strategy.

On 15 March, one of the longest motor marches in the history of the 20th began. The line of march went across the top of French North Africa, over the Atlas Mountains for more than 1,100 miles, with a trail of foxholes marking the passage through Meknes, Fez, Oujda, Tiemsen, Relizane, L'Arba, Setif and into Tunisia, the gateway of the war. Stationed in the vicinity of Kasserine, the clearing and development of roads became a top priority. On 05 April, orders came to move to Gafsa to support an anticipated counterattack by the Germans which never came.

On 15 April the 20th took to the road again. Northward through Thala, LeKef, Souk-el Arba, Lacroix and LaCalle with the Mediterranean in view. General Bradley had moved the entire II Corps from Gafsa to Northern Tunisia so smoothly and secretly that the Germans were caught unaware. On 24 April, "B" Company was attached to the Corps Franc d'Africa for engineer operations and the attack to the east began. The attack went well. The top priority of the 20th was to clear the roads of mines. The Germans were in full retreat, demolishing all bridges on their route of march. The 1st Battalion, 20th followed closely on their heels, cutting bypasses around the blown spans. The Afrika Corps fell back onto Camp Bone for a last stand. The war in Africa was over.

Although the fighting was over, the bloody days for the 20th was just beginning for the 1st Battalion. They moved into the Sedjenane Valley and began removal of the great minefields. Almost every day had its accident with a cost of dead and wounded. In mid June, the 1st Battalion rejoined the regiment at El Alia across the lake from Bizerte.

On 06 July, the regiment boarded LCT's at Bizerte Harbor and once at sea, were informed that their destination was Sicily as part of the new Seventh Army, commanded by General George Patton. On 10 July, a landing was made at Yellow Beach, 2 1/2 miles east of Licata. On 12 July, the 1st Battalion moved by truck to the extreme eastern flank of the 3rd Division and took up defensive positions. On 23 July, the 1st Battalion entered the city of Palermo, and inherited the task of clearing the docks. While the campaign was drawing to a close, the 20th was engaged in building railroad bridges. On 18 August, Rommel pulled the last of his battered troops out of the Island. The Six Weeks Campaign was over.

The first weeks of November were spent in crating baggage and turning over equipment. On 08 November, the 20th boarded the USAT "Sloterdyke" in Palermo harbor. On 24 November, they landed at Firth of Clyde, Scotland. Boarding a train in Greenock the unit moved to Prince Maurice Barracks at Devizes. Rehearsals for "Operation Overlord" and the training for the invasion of Normandy began. On 15 January 1944, 20th Engineer Regiment was broken up and its elements reorganized and redesignated as follows: 1st Battalion as the 20th Engineer Combat Battalion, Headquarters and Headquarters Service Company as Headquarters and Headquarters Company, 1171st Engineer Combat Group and the 2nd Battalion as the 1340th Engineer Combat Battalion.

On 10 February, the 20th was officially relieved from attachment to the Southern Base Section and attached to the V Corps, First United States Army. Training intensified, following a move to Wellington, England. On 01 March, the 1st Infantry Division selected the 20th to support their assault team in the invasion. On 05 June, the 20th sailed out of Portland Harbor and into the English Channel to join the greatest convey of assault craft the world had ever known. Off the coast of Normandy, their crafts crept slowly to the shore through the wreckage of boats and machines that were strewn the length of Easy Red and Fox Green Beaches. Struggling ashore, the men were pinned down among the jam of troops who could not advance in the face of brutal fire. The 16th Infantry advanced over their own dead and were able to ascend to the cliff areas. The 20th followed them, clearing mines and removing obstacles enabling the supporting vehicles to be moved off the beach. Word was passed down that the entire invasion was going as planned, in spite of the heavy resistance offered by the Germans. From 07 to 14 June the 20th supported the rapid advance of the 1st Division from Colleville through St. Honorine des Pertes, Mosles, Balleroy to Caumont by clearing mines and widening roads.

With most of the local resistance eliminated, the 20th joined in the pursuit to the east and moved through the newly liberated town lined with cheering crowds to the outskirts of Paris. On 26 August, reconnaissance parties entered Paris and took part in the glorious liberation of the capitol. With the fall of Paris, the Germans were in full flight. The 20th joined with the 28th Division who were pushing Northeast out of Paris. Clearing of road rubble from the continuous demolition of the retreating Germans became a significant task in addition of the mine clearing operations. On 11 September, the 20th entered Luxembourg. All of Northern France had been cleared of the Germans. Outstripping their supply lines, the division now had to hold fast and wait for gas and ammunition to catch with them.

"Crossing the Siegfried Line"
Once on their own soil, the Germans stiffened their lines of battle. The wait for supplies at the border had given the Germans time to shore up the West Wall defenses of the Siegfried Line. The 28th Division had driven a small wedge into the "teeth of the dragon" and the 20th had the job of maintaining the supply routes. With the beginning of autumn rains, the roads quickly became rivers of mud. Rock quarries were opened and rock was poured on the roads to keep the supplies moving. On 30 September, the Germans launched a counter attack and the 20th was put into battle as infantry to hold the enemy along the line of the Kall River. Under incessant artillery and mortar fire, this engagement became one of the most costly. By the time the 20th was relieved, 10 November, they had suffered 144 casualties, of which 103 were killed or missing in action.

In the middle of December, the Luftwaffe made appearances in greater numbers. The Germans, striking with overwhelming armored force in the thinly held areas of Bullingen, St. Vith and Clervaux, had broken through the lines and were moving West to Liege. On 20 December, the 20th was pulled out of the Hurtgen Forest and relocated to La Reid, Belgium, west of Spa. The next day, in support of the 1st Division, the 20th moved to Robertville and set up a secondary defense barrier of minefields and trees prepared for demolition. The Germans attacked strongly, but the line held. The great German drive, with the ultimate objective of reaching Antwerp and the sea and cutting off 38 Allied divisions, was losing momentum as their own supply lines stretched.

In February 1945, the thaws came, the snow vanished and under heavy traffic - the bottom dropped out of all the roads behind the front. For the first time in history, the infantry was supporting the engineers. Following the "battle of the mud" at the Ardennes, the 20th crossed the Siegfried Line again, removed mines and built a bridge at Kall. Once across the Rine, the 20th, like everyone else, moved far and fast supporting the 272nd Infantry in taking of Ehrenbreitstein, the fortress where the last American flag was lowered in World War I.

Paced by the 9th Armored Division, with the 2nd and 69th following, the 20th dashed to the outskirts of Leipzig where the Germans made a determined stand. In a short and bitter fight, the 20th lost a reconnaissance party by ambush and many were captured. Following the battle, they waited in Stossen and Wiessenfels for the historic link-up with the Russians at Torgau. On 01 May, the 20th was on the move again to Munchberg. Moving into Czechoslovakia, building a 130 foot double-double Baily bridge for the 1st Division to cross at Cheb. On 07 May, all resistance in Czechoslovakia stopped and V-E Day had arrived. The 20th had earned a little rest from their hard labor and they had time to remember old-timers who were no longer with them and think of the future that laid ahead for the battalion.

On 30 March 1946, the 20th Engineer Combat Battalion was inactivated in Frankfurt, Germany and returned to the United States.

The Korean War

On 18 September 1950, the 20th Combat Engineers was reactivated at Fort Bragg, North Carolina. On 08 June 1953, the battalion was reorganized and redesignated as the 20th Engineer Battalion. The 1954, Hurricane Hazel presented the 20th the opportunity to test its training and efficiency under emergency conditions. Clearing the ensuing damage to the streets in the towns of Wrightsville Beach and Carolina Beach, North Carolina, earned the 20th citations from both city officials and the gratitude of the townspeople.

The battalion remained on duty at Fort Bragg until 26 April 1956. At that time they relocated and were stationed at Fort Devens, Massachusetts and were assigned to perform general engineering support tasks. In October 1961, the battalion was placed on alert in response to the Cuban Missile Crisis and was rotated to Giessen, Germany where the majority of the battalion remained for a two year tour of duty. In 1963, the battalion returned to Fort Devens and resumed garrison and field training activities until the fall of 1965 when the battalion was alerted for movement to the Republic of Vietnam.

The Vietnam War

On 05 December 1965, equipment was loaded on the USNS Lt. James E. Robinson at the Boston Army Terminal. On 14 December, an advance party of the 20th left Fort Devens on C-130 aircraft and arrived in Vietnam on the 18 December. The balance of the personnel were flown to Oakland, California where they boarded the NSNS William Wiegel and sailed for Vietnam on 09 December. On 09 January 1966, the battalion arrived at Cam Rahn Bay, Vietnam and were attached to the 35th Engineer Group to provide general engineering support for the I and II Corps. Stationed at Dong Ba Thin, the battalion, with the 584th Engineer Company (Light Equipment) was engaged primarily in construction work.

On 15 June, the 20th was subsequently attached to the 45 Engineer Group. In support, the battalion highest priority was to bring the entire complex of Dong Ba Thin to grade, 6.5 feet above mean sea level using over one million cubic yards of fill. Other construction included interceptor ditches, bridges, runways, taxistrips and helipads. During 03 to 10 September, the 20th supported two companies of the 101st Airborne Division in search and destroy operations in the vicinity of Ninh Hou. On 05 October, "A" Company was re-organized as infantry, attached to the 1st Brigade, 101st Airborne Division and moved to NinH Hou for defensive operations. This operation was terminated on 13 October.

In October, the battalion was deployed in the vicinity of Pleiku where it immediately began construction of a base camp for the 4th Infantry Division. Combat operational support was provided for Operations Paul Revere II, IV and V. In support of the airborne operations, the battalion constructed 12 major airfields. Continuous effort was directed at maintaining, constructing and keeping the main overland supply routes open by the construction of bridges, clearing of mine fields and the building of new roads through the jungle.

On 01 February 1967, "C" Company relocated to Duc Lap to begin construction of a new C-130 airfield. Part of the effort included the moving of a village that was located on the center of the proposed airfield. The use of prefabricated elements greatly accelerated the accomplishments. By 15 February, six C-130 aircraft landed at the partially completed facility. On 07 April, with the completion of the airfield, "C" Company returned by convey to the Dragon Mountain Base Camp.

Throughout the operations, the heavy rains and the resulting flooding required the continuous attention of the battalion to maintain bridges, roadways and airfields. In November 1967, the battalion received the mission to upgrade the Ban Blech airfield to Class II Criteria (C-130 operations). In December, a special assignment to build an airfield at Tier Atar for the 5th Special Forces Group presented a somewhat unusual problem in that the area was unaccessible by land transportation and all equipment and supplies had to be airlifted in by CH-47 and CH-54 helicopters. Airmobile equipment was obtained from the 8th Battalion, 1st Cavalry Division.

During 1968 and through 1969, significant emphasis was placed on land clearing operations along transportation routs in addition to remote spots in order to deny the VC areas to set up ambush operations. Acceleration of the airborne operations increased the requirement for airstrip runway and landing zone maintenance. The increase in landings and aircraft loading caused extensive damage to the touchdown and turnaround areas which required complete upgrades of the subgrade and taxi surfaces.

From January 1970 to August 1971, the 20th Engineers and its attached units, the 584th Engineers (LE), 15th Engineer Company (LE) and the 509th Engineer Company (PB) provided nearly all the support for the Central Highlands. Situated near Pleiku, the battalion pursued its mission from Dak To in the North to Ban Me Thout in the South and from the Cambodian operations in the West to An Khe in the East. During the initial phases, the battalion was in process of changeover from the primary mission of providing combat support to the 4th Infantry Division to a mission with emphasis on Lines of Communication construction. Consequently, the unit was in a highly fluid state. On 20 August 1971, the battalion returned to Unites States and was stationed at Fort Campbell, Kentucky.

Persian Gulf War, Southwest Asia

In October 1990 the battalion was alerted and deployed to Saudi Arabia for Operation Desert Shield. Upon its arrival, the battalion quickly began conducting countermobility and survivability operations for the 101st Airborne Division and XVIII Airborne Corps Artillery. In Operation Desert Storm, the battalion attacked 300 miles into Iraq. During the attack, the battalion constructed logistics bases, cleared roads of obstacles and unexploded ordnance, and cleared the town of Al Busayah of enemy munitions and equipment. The battalion returned to Fort Campbell in April 1991, having earned another Meritorious Unit Citation.

Today's Cavalry

In June 1992, the 20th Engineers moved to Fort Hood, Texas to reorganize, mechanize and become an organic unit of the 1st Cavalry Division as part of the Engineer Restructure Initiative. On 16 October 1992, the unit was assigned to the 1st Cavalry Division at Fort Hood, Texas. The battalion began its conversion from a Corps "Wheeled" battalion to Divisional Mechanized Battalion. Over the next two years the battalion underwent rigorous training both at Fort Hood and the National Training Center to maximize its potential as a mechanized engineer combat unit.

"Fighting Forest Fires in Boise, ID"
In August 1994 the battalion deployed as a task force to fight forest fires in the Boise National Forest, Idaho. In the fall of 1995, "C" Company and a portion of Headquarters Company deployed with Task Force 2-8 CAV to the mountains of Korea in support of Operation Foal Eagle. The deployment trained ROK soldiers, learned the Korean landscape and culture and honed their fighting skills. In addition it has made individual or small unit deployments to Canada, Kuwait, Somalia and Honduras. Today the battalion stands, trained and ready to support the First Team anytime, anywhere in the world.