1ST First 1st Battalion, 1st Marines 1st Cavalry 1st Operations Group 1st Reconnaissance Battalion 1st Mounted Division 1st Division 1st Fighter Brigade Royal 1st Devon Yeomanry 1st Regiment 1st Senate district 3rd Battalion, 1st Marines 1st Rifle Division 1st Armoured Infantry Brigade (United Kingdom) 1st Brigade Combat Team, 1st Cavalry Division (United States) 1st Word 1st Hussars 1st Pennsylvania Regiment 1st Squadron, 1st Cavalry Regiment 1st Theater Sustainment Command 1st Belorussian Front 1st Reconnaissance Squadron 1st Marine Regiment (United States) 1st Battalion, 4th Marines 1st Brigade 1st Brigade Combat Team, 1st Infantry Division (United States) 2nd Battalion, 1st Marines 1st Armored Divi…

ision (United States) 1st & Ten 1st Airborne 1st Michigan Infantry Regiment 1st Brigade Combat Team 1st Bombardment Wing 1st Marine Division 1st Brigade (Australia) 1st Air Defense Artillery Regiment 1st Division (Thailand) 1st Constitution Bancorp 1st Armored 1st Minnesota Infantry Regiment 1st Airborne Command Control Squadron 1st (African) Division 1st Delaware Infantry Regiment 1st Armoured Brigade (United Kingdom) 1st Missouri Infantry 1st Infantry Division (United States) 1st Battle Squadron 1st Combat Engineer Battalion 1st Division (Australia) 1st Expeditionary Rescue Group 1st Horse (Skinner's Horse) 1st Light Antiaircraft Missile

Battalion 1st Canadian Parliament 1st Colorado Infantry Regiment 1st Fighter Squadron 1st Infantry Regiment (United States) 1st Fighter Wing Francis Cook, 1st Viscount of Monserrate 1st Foreign Regiment (France) 1st Georgia Infantry Regiment 1st Cavalry Division (United States) 1st (Peshawar) Division 1st Test and Evaluation Squadron 1st Brahmans 1st Light Car Patrol (Australia) 1st Marine Expeditionary Brigade (United States) 1st Special Operations Squadron 1st Royal New South Wales Lancers 1st Anti-Aircraft Brigade 1st millennium BC 1952–53 Danish 1st Division Oita 1st district 1947–48 Danish 1st Division 1955–56 Dan