The Bihar Regiment is an Indian Army infantry regiment. It traces its origins back to the British Indian Army. The Bihar Regiment was formed in 1941 by regularising the 11th (Territorial) Battalion, the 19th Hyderabad Regiment, and raising new battalions. The Bihar Regimental Centre (BRC) is located at Danapur Cantonment, Patna, the second oldest cantonment of India. INS Vikramaditya, the Indian Navy's largest ship and its sole aircraft carrier is affiliated to the Bihar Regiment, Indian Army's highly decorated and battle-hardened unit. The regiment also distinguishes itself by having the highest number of Rashtriya Rifles battalions (4 battalions: 4RR, 24RR, 47RR, 63RR) among all regiments of the Indian Army.