To designate the facility of the United States Postal Service located at 135 Main Street in Biloxi, Mississippi, as the "Robert S. McKeithen Post Office Building".

Designates the Biloxi post office as the Robert S. McKeithen Post Office Building. The law gives the United States Postal Service facility at 135 Main Street in Biloxi, Mississippi that official name and directs federal laws, maps, regulations, documents, papers, and other records to refer to it by that name. The change is purely nominal and updates only the facility's official designation in federal records.