The 1st and 2nd battalions of the 2nd Engineers participated in the Battle of Belleau Wood in direct support of the 4th Marine Brigade of the US Army's 2nd Division. Elements of the 2nd Engineers provided engineering support and fought as infantry throughout the battle. "There was always good feelings between the Marines of the 2d Division and the Regular Army units that formed it, but the Marines and the 2d Engineers – 'Say, if I ever get a drink, a 2d Engineer can have half of it! – Boy they dig trenches and mend roads all night, and they fight all day!'" -John Thomason.