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.

Livingston Parish (French: Paroisse de Livingston) is a parish located in the U.S. state of Louisiana. Livingston Parish is known as one of the eight Florida Parishes, a region of Louisiana that was bought from Spanish Florida, and created the modern day state borders. It is widely accepted that the name Livingston is an eponym honoring Edward Livingston, a prominent American and Louisianan, a jurist and statesman who assisted in the drafting of the Louisiana Civil Code of 1825.Livingston Parish is part of the Baton Rouge metropolitan statistical area. At the 2010 census, the population was 128,026; the 2019 American Community Survey estimated its population was 138,928. The 2020 census tabulated an increase at 142,282.Its parish seat is located in the town of Livingston. Livingston Parish is also part of Louisiana's 6th Congressional District.

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.

St. John the Baptist Parish (SJBP, French: Paroisse de Saint-Jean-Baptiste) is a parish located in the U.S. state of Louisiana. At the 2020 census, the population was 42,447. The parish seat is Edgard, an unincorporated area, and the largest city is LaPlace, which is also unincorporated. St. John the Baptist Parish was established in 1807 as one of the original 19 parishes of the Territory of Orleans, which became the state of Louisiana.St. John the Baptist Parish is part of the New Orleans–Metairie metropolitan statistical area. This was considered part of the German Coast in the 18th and 19th centuries, named for numerous German immigrants who settled along the Mississippi River here in the 1720s. On January 8, 1811, the largest slave insurrection in US history, known as the German Coast Uprising, started here. It was short-lived, but more than 200 slaves gathered from plantations along the river and marched through St. Charles Parish toward New Orleans. This is part of the Sugarland or sugar parishes, which were devoted to sugar cane cultivation. Planters used large numbers of enslaved African-American workers before the war, and numerous freedmen stayed in the area to work on these plantations afterward. The parish includes three nationally significant examples of 19th-century plantation architecture: Evergreen Plantation, Whitney Plantation Historic District, and San Francisco Plantation House.