When the United States declared war on Germany on 11 April 1917, the Wisconsin Adjutant General ordered the Milwaukee troops to add a squadron, and Troop C and Troop D were added. The Guard units' Troop A and Troop B had been mustered out of federal service less than a year earlier on 20 October 1916 and 6 March 1917, respectively. The Adjutant General then directed the unit to add a new regiment, and the Second and Third Squadrons were formed as the First Wisconsin Cavalry, with units organized in various cities. Troop E commanded by Captain John S. Coney was formed in Kenosha on 10 May 1917, and the Wisconsin Cavalry was officially formed on 29 May 1917.