Final answer:
Michigan contributed to the Civil War by supplying a significant number of troops to the Union effort, in addition to producing war materials, to maintain its stance as a free state against the Confederacy.
Step-by-step explanation:
During the Civil War, Michigan was a free state and part of the Union that did not witness any battles on its ground, yet it played a significant role by supplying a number of troops to the Union Army. While the state also contributed in other aspects such as producing war materials and serving as an Arsenal of Democracy, particularly in Detroit, its key contribution came in the form of manpower to support the Union forces. The response from state militias to President Lincoln's call was overwhelming and not only from Michigan but also from other Northern states, making it possible for the Union to exceed its requisition. Furthermore, Michigan's status as a free state, following the provisions of the Northwest Ordinance, solidified its position against the Confederacy from its inception as a state.