Livingston's signature is not on the Declaration of Independence because he was in New York during the signing.

CREDIT: Horydczak, Theodor, photographer. "Signing of the Declaration of Independence, Painting by John Trumbull in U.S. Capitol." Circa 1920-1950. Washington as It Was: Photographs by Theodor Horydczak, 1923-1959, American Memory collections, Library of Congress.