Mandeville is a city in St. Tammany Parish, Louisiana, United States. The population was 11,560 at the 2010 U.S. census, and 13,192 at the 2020 United States census. Mandeville is located on the north shore of Lake Pontchartrain, south of Interstate 12. It is across the lake from the city of New Orleans and its south shore suburbs. It is part of the New Orleans–Metairie–Kenner metropolitan area.
Washington Parish (French: Paroisse de Washington) is a parish located in the interior southeast corner of the U.S. state of Louisiana, one of the Florida Parishes. As of the 2010 census, the population was 47,168. Its parish seat is Franklinton. Its largest city is Bogalusa. The parish was founded in 1819.Washington Parish comprises the Bogalusa, LA Micropolitan Statistical Area, which is included in the New Orleans-Metairie-Hammond, LA-MS Combined Statistical Area.
Tangipahoa Parish ( ; French: Paroisse de Tangipahoa) is a parish located in the southeast of the U.S. state of Louisiana. As of the 2010 census, the population was 121,097. The parish seat is Amite City, while the largest city is Hammond. Southeastern Louisiana University is located in Hammond. Lake Pontchartrain borders the southeast side of the parish. The name Tangipahoa comes from an Acolapissa word meaning "ear of corn" or "those who gather corn." The parish was organized in 1869 during Reconstruction.Tangipahoa Parish comprises the Hammond, LA Metropolitan Statistical Area, which is also included in the New Orleans-Metairie-Hammond, LA-MS Combined Statistical Area. It is one of what are called the Florida Parishes, at one time part of West Florida.