The 2nd regiment was formed from ten militia companies from southern Michigan. The militia companies were generally too small for active service and new recruits were gathered to fill the ranks. During late April and early May of 1861 the regiment was filled and ready to enter service. On May 25, the regiment was mustered into active duty as the first "3 years" regiment and in early June departed Fort Wayne at Detroit for Washington D.C. The 2nd served well until the 29th of July 1865.