1767 Map of West Florida
     Washington Parish was formed in 1819 by splitting off from St. Tammany Parish. Franklinton became the parish seat on 10 February 1821. It is one of the eight "Florida Parishes" lying east of the Mississippi River and north of Lakes Pontchartrain and Maurapas in present day Louisiana. The others are St. Tammany, Tangipahoa, St. Helena, Livingston, East and West Feliciana and East Baton Rouge. They are so called because this territory was once part of West Florida, and for a brief period in 1810, the Free and Independent Republic of West Florida.

     From 1682 until 1763, this region was a part of the French colony of Louisiana. At the end of the French and Indian War in 1763, France ceded most of Louisiana to Spain, but gave Canada and the territory King George would soon name West Florida, to England. During the sixteen years of British hold on West Florida, land grants were given to retired British soldiers, and during the revolutionary years, Tories moved there to escape persecution.

     Spain supported the United States during the Revolution, and in the only American Revolution battle fought in Louisiana, Louisiana's Spanish governor Galvez routed the British out of West Florida. Then, in the Treaty of Paris that ended the war in 1783, Britain ceded the territory back to Spain. Soon after, the area was divided into Baton Rouge, St. Helena, Chifoncte (later St. Tammany), and Feliciana, after Felicite, the wife Galvez. The landowners were allowed to remain if they swore loyalty to the Spanish crown and embraced Catholicism, but the decree was poorly enforced. There followed a long period of social chaos, crime and political unrest in Spanish West Florida.

     The Louisiana Purchase in 1803 included no part of West Florida because, the Spanish claimed, Napoleon could not sell land he did not own. Finally in 1810, some 500 inhabitants of Feliciana, all Spanish subjects, voted with only eleven dissenting to assume self-government. On 23 September 1810, 75 rebels overcame the Spanish garrison at Baton Rouge and raised the flag of the Republic of West Florida, a single white star on a blue background.

     The Republic of West Florida was short-lived. On 27 October 1810, by proclamation of President James Madison who claimed the region as part of the Louisiana Purchase, West Florida were annexed by the United States and became part of the Louisiana Territory. However, when Louisiana became a state on 30 April 1812, the Florida Parishes were not included. Four days later, Congress passed an act to enlarge the state to include West Florida, and four months later it was made official by the state legislature.