Constituted in the Illinois State Guard as the 1st Battalion of Infantry and organized 14 September 1874 in Chicago from the following companies raised entirely by subscription: • Company A, Captain Graeme Stewart; • Company B, Captain Edwin B. Knox; • Company C, Captain Mason B. Carpenter; • Company D, Captain John W. Hawley. • Expanded and redesignated as 1st Regiment of Infantry, Illinois State Guard, 5 October 1874. • Redesignated as 1st Regiment, Illinois State Guard, 21 December 1875. (Illinois State Guard redesignated Illinois National Guard 1 July 1877.) • Mustered into Federal service at Springfield, 13 May 1898 as 1st Illinois Volunteer Infantry; served in Cuba and mustered out 17 November 1898 at Chicago. • Mustered into Federal service 26 June 1916 for Mexican Border and stationed at San Antonio, Texas; mustered out 4 October 1916. • Mustered into Federal service 4 April 1917; drafted into Federal service 5 August 1917. Redesignated as the
131st Infantry and assigned to the
33rd Division 12 October 1917. • Demobilized 6 June 1919 at
Camp Grant (Illinois). • Reorganized during June 1919 as the 1st Infantry, Illinois National Guard. • Redesignated as the 131st Infantry and assigned to the 33d Division 13 December 1921. • Federally recognized 18 August 1922 at Chicago. • Inducted into Federal service 5 March 1941 at Chicago. Relieved from the 33d Division 21 February 1942. • Inactivated 26 February 1944 at
Fort Benning, Georgia. • Assigned to the 33d Infantry Division 5 July 1946. Reorganized and Federally recognized 20 December 1946 at Chicago. • consolidated on 15 March 1954, with the
132nd Infantry Regiment (United States) and the consolidated unit designated as the 131st Infantry, an element of the 33rd Infantry Division. • Relieved from the 33d Infantry Division 1 March 1959 and reorganized as the 131st Infantry, a parent regiment under the
Combat Arms Regimental System·to consist of the 1st Battle Group, an element of the 33d Infantry Division. • reorganized on 1 April 1963 to consist of the 1st Battalion, an element of the 33d Division; • reorganized on 1 December 1965 to consist of the 1st Battalion; • reorganized on 1 February 1968 to consist of the 1st Battalion, an element of the
33rd Infantry Brigade (United States). • ordered into active Federal service on 7 April 1968 at Chicago. It was released from active Federal service on 11 April 1968 and reverted to state control. • withdrawn on 5 February 1987 from the Combat Arms Regimental System and reorganized under the
United States Army Regimental System with headquarters in Chicago. ==Distinctive unit insignia==