This chapter traces Irish immigration to Wisconsin and the formation the 17th Wisconsin Volunteer Infantry. When war broke out in 1861 the Irish in Wisconsin were slow to rise in unison in defense of the Union. A relatively stable immigrant community, many Irish chose, early in the war, to enlist in ethnically mixed regiments—illustrating the inclusive communities that developed in this Midwestern state during the antebellum period. In winter of 1862, though, vocal Irishmen, playing upon the success of other ethnic units, were given the opportunity to form their own regiment, the 17th Wisconsin. Publicly declaring their allegiances to the Irish American community, Wisconsin’s Irish regiment was, in reality, an ethnically diverse unit that attracted men from across the state. As the regiment prepared to move south in the spring of 1862, though, tensions rose and a large number of men mutinied. Supported by local newspaper editors, the demands of these men were seen as expressions of republicanism, illustrating (when compared to the experiences of the Ninth Connecticut) the diverse responses to Irish conduct in communities throughout the north, and the ways these men understood their military service.