The U.S. Postal Service, which has seen a 25 percent decline in first-class mail since 2006, has announced it will close mail processing centers in four Mississippi cities, including Grenada. Mail processing operations in Grenada will move to Jackson. Elsewhere, operations in Gulfport and Hattiesburg will move to Mobile in Alabama and operations in Tupelo will move to Memphis. Dates for the consolidation have not yet been announced.