The 4th Rifle Brigade was a rifle formation of the army infantry of the Russian Imperial Army.
The brigade received the unofficial name "Iron Brigade" after the Russo-Turkish War of 1877–1878, in which its units (the 13th, 14th, 15th, and 16th Rifle Battalions) took a prominent part in the most difficult operations of that war, which required the utmost exertion of physical and moral strength (the crossing of the Danube near Zimnitsa on 21 June (3 July), the Trans-Balkan campaign of General Gurko's Advance Detachment, the relief of Shipka, etc.), and in a hard struggle against superior Turkish forces and the harsh conditions of the highlands demonstrated high combat qualities. The brigade was again given the name "Iron" during World War I under the command of Major General A. I. Denikin, for steadfastness and the flawless execution of command assignments.