Plaquemines Parish is the parish with the most combined land and water area in Louisiana. The parish seat is Pointe à la Hache. As of 2000, the parish's population was 26,757.

The name "Plaquemines" was derived from French Creole and the Atakapa word, piakimin, meaning persimmon. The French used it to name a military post they built on the banks of the Mississippi, a site surrounded by numerous persimmon trees. Eventually the name was applied to the entire parish and to a nearby bayou.

The oldest European settlement in the parish was La Balize, where the French built and inhabited a crude fort by 1699 near the mouth of the Mississippi River. The name in French meant "seamark", a tall structure of wood built as a guide for ships. The French built one 62 feet (19 m) high by 1721. A surviving map from about 1720 shows the island and fort, and the mouth of the river.

As traffic and trade on the river increased, so did the importance of river pilots who were knowledgeable about the complicated, ever-changing currents and sandbars in the river. They lived at La Balize with their families. The village was destroyed and rebuilt numerous times, but it was abandoned for good after the destruction of a September 1860 hurricane. The pilots moved upriver and built the settlement they named Pilottown, which reached its peak of population in the 19th century. The river pilots' expertise continues to be critical, but now they generally live with their families in more populated areas, and stay at Pilottown temporarily for work.

An important historical site is Fort Jackson, built in 1822 as recommended by General Andrew Jackson, hero of the Battle of New Orleans in the War of 1812. In 1861, Fort Jackson served as an important Confederate defense for the city of New Orleans during the Civil War because it was at the mouth of the Mississippi River. The US Army used it as a training base during World War I, 1917-1918.

Because Plaquemines Parish encompasses the first 70 miles (110 km) of the Mississippi River, it is the site of several oil refineries, which rely on the shipping lanes for moving their product. The Mississippi River Delta of Plaquemines is also a base for assistance to offshore oil rigs. Plaquemines Parish was the first place in the United States where shippers used a container for cargo in foreign trade.

The August 1901 Hurricane caused damage, including 4 feet of water in Buras.

In the early 1900s, Plaquemines was an exporter of citrus. Farmers used the railroads and the Mississippi to ship the large annual harvest to markets. Commercial fisheries, especially for oysters, have been important in the parish economy.

The Great Hurricane of 1915 devastated much of the Parish, with multiple levee breaches on both sides of the Mississippi, a 12-foot storm surge, and hundreds of deaths. Homelessness was widespread, and many people were reduced to starvation until charitable aid arrived. The old Parish Courthouse in Pointe à la Hache was among the many buildings destroyed in the storm, but a new one was completed within the year.

From 1919 to 1969, Plaquemines and St. Bernard parishes were effectively the domain of the political boss Leander Perez, who established a virtual dictatorship in the area.  He was notorious for fixing elections and enforcing strict racial segregation. Upon his death, his sons Leander Perez Jr. and Chalin Perez were elected as the dominant political figures of the parish as district attorney and parish president, respectively. Interpersonal feuding weakened the family's hold on power, and by 1980, political opponents had begun to win local elections.

During the Great Mississippi Flood of 1927, city and state leaders used dynamite to breach a levee at Caernarvon, thirteen miles (19 km) below Canal Street, in order to save the city of New Orleans from flooding. This action resulted in the flooding of much of the less-populated St. Bernard and Plaquemines parishes, causing widespread destruction to agriculture and housing.

In 1965 Hurricane Betsy damaged the area, flooding many buildings, including the Parish Courthouse, and causing nine deaths. Leander Perez sealed off the Parish from the outside world, while trying to control state assistance.

Birth Records - The Louisiana State office maintains records for 100 years after the date of birth. Birth records are considered confidential for the first 100 years. For current information on who may obtain a birth record as well as how to submit a request visit the Office of Public Health, Vital Records Registry website or write to them at PO Box 60630, New Orleans, LA 70160.

Birth records older than 100 years are available through the Louisiana State Archives, 3851 Essen Lane, Baton Rouge, LA 70809. (225) 922-1000.

Death Records - The Louisiana State office maintains records for 100 years after the date of death. Death records are considered confidential for the first 100 years. For current information on who may obtain a death record as well as how to submit a request visit the Office of Public Health, Vital Records Registry website or write to them at PO Box 60630, New Orleans, LA 70160.

Death records older than 100 years are available through the Louisiana State Archives, 3851 Essen Lane, Baton Rouge, LA 70809. (225) 922-1000.

Marriage Records - For current information on how to submit a request for a certified copy of an Orleans Parish marriage record less than 50 years old, see the Louisiana Office of Public Health Director, Vital Records and Statistics website or write to PO Box 60630, New Orleans, LA 70160.

Certified copies for the parish are issued by Clerk of Court. For the address of the parish Clerk of Court visit the Plaquemines Parish Important Addresses page.

Marriage records over 50 years are stored by the Louisiana State Archives, 3851 Essen Lane, Baton Rouge, LA 70809. (225) 922-1000.

Divorce Records - To obtain current information on how to submit a request for a certified copy of divorce records contact the Clerk of Court. For the address of the parish Clerk of Court visit the Plaquemines Parish Important Addresses page.