The 73rd New York Infantry Regiment was an infantry regiment of Union Army in the American Civil War. The regiment was organized in New York City in May 1861, originally under the designation the Fourth Excelsior Regiment, as a Zouave regiment, known for its unusual dress and drill style. The uniform worn by this regiment consisted of a dark blue chasseur jacket with light blue trim and light blue trefoils on each sleeve, sky blue chasseur trousers with two white stripes down each leg, brown leather gaiters, a light blue kepi with a dark blue band and dark blue piping, and a red Zouave fez with a blue tassel as a fatigue cap.