The 6th Air Defense Artillery Regiment is an air defense artillery regiment in the United States Army, first formed in 1898 as the 6th Regiment of Artillery. The 6th and 7th U.S. Artillery Regiments were constituted on 8 March 1898, three weeks after the explosion of the USS Maine in Havana, Cuba on 15 February 1898, as the United States' declaration of war on Spain and commencement of the Spanish–American War seemed imminent.