Walnut Street Historic District is a national historic district located at Muncie, Delaware County, Indiana. It encompasses 66 contributing buildings and 1 contributing object, and is located in the central business district of Muncie. The district includes notable examples of Italianate, Late Victorian, Colonial Revival, and Beaux-Arts style architecture. Located in the district are the separately listed Moore-Youse-Maxon House, Roberts Hotel, and Goddard Warehouse. Other notable buildings include the Patterson Bock (c. 1876), McNaughton Block (1901-1903), Mitchell Block (1909), American National Bank Building (1924), Marsh Block (1888), and the Old Post Office designed by the Office of the Supervising Architect under James Knox Taylor (1907, 1930).: 50–53 It was added to the National Register of Historic Places in 1989.