The regiment's coat of arms and its distinctive unit insignia reflect its history. The regiment was originally formed in Arizona from elements of the 11th, 18th, and 22d Infantry Regiments. These organizations are represented on the canton of the crest, in the upper left-hand corner. The white Maltese cross represents the 11th Regiment, the red acorn represents the 18th Regiment, and the embattled partition line of the canton represents the 22nd Regiment. The cactus represents the original service along the Mexico–US border against the revolutionaries of General Francisco Villa.