The Walnut Street Bridge is a historic Pratt through truss bridge over the North Fork of the Zumbro River in Mazeppa, Minnesota, United States. It was built as a highway bridge in 1904 but has been restricted to pedestrian use since 1980. It was listed on the National Register of Historic Places in 2003 for having local significance in the theme of engineering. It was nominated for being the work of noted Minnesota engineer William S. Hewett and his bridge building firm the W. S. Hewett Co., an example further recognized for its exceptional ornamentation.