The 3d United States Infantry Regiment, "The Old Guard" will march in the Washington, DC Saint Patrick's Day Parade at 12pm on Sunday March 15, 2009. Spectators along Constitution Avenue from 7th to 17th Streets can expect to see two marching units from the Army's oldest active-duty Infantry Regiment including the Fife and Drum Corps and an infantry platoon from E Company, 4th Battalion, 3rd Infantry Regiment.