The 129th Infantry Regiment is a United States military unit of the Illinois National Guard. The 129th served in World War I and World War II.

The 33rd Infantry Division was a formation of the U.S. Army National Guard between 1917 and 1968. Originally formed for service during World War I, the division fought along the Western Front during the Battle of Amiens, the Battle of Hamel, the Meuse-Argonne Offensive, at the Second Battle of the Somme, and at the Battle of Saint-Mihiel. It was re-formed during the inter-war period, and then later activated for service during World War II, seeing action against the Imperial Japanese Army in the Pacific. In the post war era, the division was reconstituted as an all-Illinois National Guard division. In the late 1960s, the division was reduced to a brigade-sized formation, and its lineage is currently perpetuated by the 33rd Infantry Brigade Combat Team.