The Moodna Viaduct is an iron railroad trestle that spans the Moodna Creek and its valley at the north end of Schunemunk Mountain in Salisbury Mills, New York. The bridge was constructed between 1904 and 1908 by the Erie Railroad as part of the Graham Line and was opened for service in January 1909. The trestle spans the valley for 3,200 feet (975m) and is 193 feet (59 m) high at its highest point, making it the highest and longest railroad trestle east of the Mississippi River. The open design of the trestle was used to reduce wind resistance and is a major reason why the trestle is still in service today. The viaduct crosses Orrs Mills Road north of the creek and Otter Kill Road south of the creek.