 The Michigan unit was one of three engineering regiments raised in 1861, the other two being Missouri (August 1861) and New York (September 1861).Engineering regiments are often left off of many Order of Battles, but their contribution to campaigns were vital from a logistics point of view; repairing/building railroads, bridges and blockhouses; and destroying enemy communication lines, railroads and bridges.Engineering units like the First Michigan were often caught up in attacks from enemy guerrillas and cavalry skirmishes.