 Following the cessation of hostilities, on 1 July 1866, The United States Engineer Battalion was redesignated the "1st Battalion of Engineers".The battalion's first Sergeant Major, Frederick W. Gerber, was awarded the Medal of Honor for his 25 years of service to the battalion, which included the Mexican–American War and the American Civil War.During the Spanish–American War, Company C and Company E of the battalion were sent to Cuba where they fought in the campaign to take the city of Santiago.