4th Wisconsin Volunteer Regiment

4th Regiment Wisconsin Volunteer Infantry
Flag of Wisconsin
Active	July 2, 1861 – June 19, 1866
Allegiance	Federal
Branch	Infantry
Type	Regiment
Engagements	American Civil War
Commanders
Notable commanders	Halbert E. Paine Joseph Bailey

The 4th Wisconsin Volunteer Regiment was an infantry regiment that served in the Union Army during the American Civil War, primarily in the Western Theater. It was later mounted and became the 4th Wisconsin Volunteer Cavalry Regiment.

The 4th Wisconsin was raised as an infantry regiment at Camp Utley in Racine and was mustered into Federal service on July 2, 1861. It was first assigned to garrison duty in Maryland, then in February 1862 was transferred to Newport News, Virginia. It became part of the Army of the Gulf and was subsequently sent to New Orleans, Louisiana. During the following year, the 4th Wisconsin participated in several expeditions against Vicksburg, Mississippi, and Port Hudson, Louisiana. It saw action in the Siege of Port Hudson from May to July 1863.

On September 1, 1863, the regiment was reorganized as the 4th Wisconsin Volunteer Cavalry Regiment, which it served as through the remainder of the war.

The 4th Wisconsin Regiment initially mustered 1,058 men and later recruited an additional 994 men, for a total of 2502 men during its service. The regiment lost 9 officers and 158 enlisted men killed in action or mortally wounds, plus another 2 officers and 113 enlisted men who died of disease, for a total of 282 fatalities.