US Post Office—Fredonia is a historic post office building located at Fredonia in Chautauqua County, New York, and within the boundaries of the Fredonia Commons Historic District. It was designed and built in 1935–36 as a Works Progress Administration project, 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, Louis A. Simon. It is a one-story, five bay brick structure set on a brick foundation in the Colonial Revival style. The central section features three large round arched openings with cast-stone keystones. The interior features "The Harvest"; a mural from 1937 by artist Arnold Blanch. It was listed on the National Register of Historic Places in 1989.