The 66th Division was activated on April 15, 1943 at Camp Blanding, Fl. Its commander, Major General Herman F. Kramer, continued with the division until August 1945, when he was relieved by Major General Walter F. Lauer. General Lauer commanded the division until its deactivation in November 1945. The 66th Division was part of the Sixth Army Group and participated in the Northern France campaign.

An Engineer Combat Battalion (ECB) was a designation for a battalion-strength combat engineer unit in the U.S. Army, most prevalent during World War II. They are a component of the United States Army-Corps of Engineers.

Also known as "Combat Engineer Battalions", they were typically divided into four companies: A, B, C, and Headquarters and Service.