US Post Office-Penn Yan is a historic post office building located at Penn Yan in Yates County, New York. It was designed and built in 1912–1913 and is one of a number of post offices in New York State designed by the Office of the Supervising Architect of the Treasury Department, James Knox Taylor. It is a symmetrically massed, 1 1/2-story red brick structure on a granite-clad raised basement in the Colonial Revival style. It is a contributing element in the Penn Yan Historic District. It was listed on the National Register of Historic Places in 1989.