|August 15, 1862. "Today I enlisted as a soldier in the army of the United States. How changed everything seems to me now.... I must soon leave home, friends, and the old familiar things of boyhood days, to go forth amid the dangers, privations and hardships of the soldier's life.... I am going under Capt. Williams in the 28th Regiment of Wisconsin Volunteers, Co. A. We go into camp at Milwaukee on the 13th day of September, 1862."
-- Diary of Corp. Charles H. Wildish
The Twenty-eighth Regiment was recruited during the summer of 1862 in Waukesha and Walworth Counties, Wisconsin, and was organized at Camp Washburn, Milwaukee, under the command of Colonel James M. Lewis of Oconomowoc. Ten companies of a bit less than 100 men each had responded to President Lincoln's second call for volunteers. Six companies were recruited from Waukesha County and four raised in nearby Walworth County. Many companies carried their own descriptive names, such as the , , , , and .
The 28th Regiment was mustered into United States service on 13 October 1862. They spent the next nine weeks training at Camp Washburn, near Milwaukee, before boarding railcars and heading south on December 20, 1862.