The 26th Engineer Battalion (Combat) was constituted as a unit of the Regular Army on December 1, 1954 and on December 2, 1954 was activated as an element of the 23rd Infantry Division at Fort Clayton, Canal Zone. At that time, the Battalion was composed of Company A which was organized February 1, 1945 as the 2920th Dump Truck Company, Company B and Headquarters Company, the initial organization for each, and Company C which was organized on April 7, 1944 as the 406th Engineer Combat Company. The 26th Engineer Battalion (Combat) was inactivated on April 10, 1956.
On December 8, 1967, in the Republic of Vietnam, the 26th Engineer Battalion (Combat) was again activated as the organic combat engineer battalion of the 23rd Infantry Division (Americal).
The 26th Engineer Battalion is composed of four Combat Engineer line companies, a Float Bridge Company, and a Headquarters and Headquarters Company. Company A was formerly the 175th Engineer Company, organic to the 196th Light Infantry Brigade. Its headquarters is now at Fire Support Base Hawk Hill in direct support of the 196th Infantry Brigade. Company B was the 555th Engineer Company, organic to the 198th Light Infantry, and Company C was formerly the 6th Engineer Company, 11th Light Infantry Brigade. Company B now continues its direct engineer support to the 198th Infantry Brigade with headquarters at Landing Zone Bayonet. Company C remains with the 11th Infantry Brigade at Fire Support Base Bronco in Duc Pho, Republic of Vietnam. Company D was formed primarily from elements of Company B, 39th Engineer Battalion (Combat) which was attached to th Americal Division at the time of activation. The 554th Engineer Company (Float Bridge) was transferred from the 39th Engineer Battalion (combat) and redesignated Company E, 26th Engineer Battalion (Combat). Headquarters Company was formed from elements of the USARV Engineer Command.
Source: the americal division, "under the southern cross" - published by the U.S. Army in 1971.