High Quality Content by WIKIPEDIA articles! Indiana, a state in the Midwestern United States, played an important role during the American Civil War. Despite significant anti-war activity in the state and southern Indiana`s ancestral ties to the Southern United States, it did not secede from the Union. During the course of the war, Indiana contributed approximately 210,000 soldiers and millions of dollars of equipment and supplies to the Union. Residents of Indiana, also known as Hoosiers, served in every major engagement of the war and almost every engagement—minor or otherwise—in the western theater of the war. Indiana, an agriculturally rich state containing the fifth-highest population in the Union and sixth-highest of all states, was critical to Northern success.