The town was founded by F. Mortimer Thorp in 1885 and was platted as a town site on July 13, 1895. The name was chosen by the Northern Pacific Railway to honor Milford A. Thorpe, a member of this well-known pioneer family. Thorp Grist Mill a well-preserved mill, constructed in 1883 to serve the community of Thorp as it developed within the floodplain of the Yakima River, is now home to the Thorp Mill Town Historical Preservation Society. While tours of the National Register-listed mill can be arranged during the summer months (call 509-964-9640), a self-guided walking tour around the perimeter of the mill can be taken year-round and includes informative signage interpreting the history of this historic site.