Iberville was "discovered" by French explorer Pierre LeMoyne, Sieur d'Iberville in 1699, but its rich delta soil and many waterways had been discovered by Indian tribes long before Iberville ever set foot here. While it was initially an agricultural area, Iberville has changed through the centuries to accommodate the changing times. The Parish has always had plenty of sugarcane and soybean fields, but through the years the hardwood timber industry, river commerce and now industrial development have been essential to a thriving parish economy.
From the 1800s until the mid-1900s Louisiana produced more sugar than any other state in the nation, and Iberville, as the state's leading sugarcane producer, drew the name "Sweet Iberville." By the late 1800s Bayou Plaquemine, running through the heart of Iberville, became the most common route from the Mississippi River into the interior of Louisiana, and this water traffic brought a boom in the parish's timber and sawmill industries and a variety of commercial establishments catering to travelers. It also resulted in the construction of the historic Plaquemine Lock.
With the agricultural, timber, sawmill and water commerce industries powering the economy, Iberville prospered into the 1960s when the lock was finally closed, replaced by a bigger structure closer to Baton Rouge. But by this time the chemical industry had realized the many advantages that Iberville offered with its access to the Mississippi River, interstate travel, electrical power and hard-working people. Today, the chemical and agriculture industries power the economy and exist in harmony with the tourism industry.
The City of Plaquemine, the Parish Seat, is nestled on pre-historic Bayou Plaquemine, a tributary of the mighty Mississippi River. The earliest map shows Plaquemine as a settlement in 1775. The Chitimacha Indians were living here when Pierre LeMoyne, Sieur de Iberville arrived in 1699 and claimed all of Louisiana for King Louis XIV of France. It took its name from the Indian word Plaquemine, which means persimmons. The city became the seat of parish government in 1835 and was incorporated in 1838.
Plaquemine became an important trading center as Bayou Plaquemine served as a natural waterway to the western interior of Louisiana. It served as a transportation route of agriculture, lumber, fishing, and oil and gas industries of the area during the early 19th century.
Today, a new day of progress and activities has begun in the revitalizing development of the city. Plaquemine’s downtown historic district consists of 120 residential and business buildings listed on the National Register of Historic Places. The Plaquemine Depot Market, featuring a market of arts and crafts, is located in the 1925 Union Pacific Railroad Depot downtown. Iberville Museum is housed in the former Iberville Parish Courthouse (c. 1848), which served as City Hall from 1906 to 1985. It is now open with a varied display of historic artifacts, near the Plaquemine Locks State Historic Site.
The parish has a total area of 653 square miles, of which 619 square miles is land and 34 square miles (5.21%) is water. The population in the 1900 Federal Census was 27,006. In 2000 the Federal Census showed a population of 33,320.
Neighboring parishes are Pointe Coupee Parish (northwest), West Baton Rouge Parish (north), East Baton Rouge Parish (northeast), Ascension Parish (east), Assumption Parish (southeast), Iberia Parish (south), and St. Martin Parish (west). Communities in the parish include Bayou Pigeon, Bayou Sorrell, Crescent, Grosse Tete, Maringouin, Plaquemine, Rosedale, St. Gabriel, and White Castle.