Jefferson Parish (French: Paroisse de Jefferson) is a parish in the state of Louisiana. As of the 2010 census, the population was 432,552. The parish seat is Gretna.
According to the U.S. Census Bureau, the parish has a total area of 665 square miles (1,720 km), of which 296 square miles (770 km) is land and 370 square miles (960 km) (56%) is water.
Lake Pontchartrain is situated in the northern part of Jefferson Parish with the parish line several miles north of the southern shore, with St. Tammany Parish at its northern shore. The Mississippi River is located around the midpoint of Jefferson Parish flowing generally in a north-west to south-east direction.
Surrounding parishes include St. Tammany Parish, Louisiana at the north shore of Lake Ponchartrain, St. Charles Parish upriver to the west, Orleans Parish downriver to the east, and Plaquemines Parish downriver to the south-east. The majority of the southern half of Jefferson Parish is uninhabited marshland with one of the exceptions being the town of Grand Isle; the only roads connecting Grand Isle to the rest of Jefferson Parish run through Lafourche Parish and St. Charles Parish.
As of the 2010 census, there were 432,552 people living in Jefferson Parish. The population density was 1,410 people per square mile (574/km²). There were 187,907 housing units at an average density of 613 per square mile (237/km²). The racial makeup of the parish was 60.82% White, 25.08% Black or African American, 0.68% Native American, 5.28% Asian, 0.13% Pacific Islander, 2.53% from other races, and 1.82% from two or more races. 14.85% of the population were Hispanic or Latino of any race.
As of the 2000 census, there were 455,466 people living in Jefferson Parish. The population density was 1,486 people per square mile (574/km²). There were 187,907 housing units at an average density of 613 per square mile (237/km²). The racial makeup of the parish was 69.82% White, 22.86% Black or African American, 0.65% Native American, 3.09% Asian, 0.08% Pacific Islander, 2.18% from other races, and 1.65% from two or more races. 7.12% of the population were Hispanic or Latino of any race.
There were 176,234 households out of which 31.90% had children under the age of 18 living with them, 48.20% were married couples living together, 15.40% had a female householder with no husband present, and 31.80% were non-families. 26.70% of all households were made up of individuals and 8.40% had someone living alone who was 65 years of age or older. The average household size was 2.56 and the average family size was 3.13.
In the parish the population was spread out with 25.30% under the age of 18, 9.10% from 18 to 24, 30.20% from 25 to 44, 23.40% from 45 to 64, and 11.90% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 92.40 males. For every 100 females age 18 and over, there were 88.60 males.
The median income for a household in the parish was $38,435, and the median income for a family was $45,834. Males had a median income of $35,081 versus $24,921 for females. The per capita income for the parish was $19,953. About 10.80% of families and 13.70% of the population were below the poverty line, including 20.00% of those under age 18 and 9.80% of those age 65 or over.
Between the 2000 U.S. Census and the 2010 U.S. Census the population of Jefferson Parish decreased while the population of Hispanics increased. Greg Rigamer, a consultant of WWL-TV Eyewitness News, a chief executive officer of GCR and Associates, and a demographer stated. He argued that the population increased because Hispanics came after Hurricane Katrina in 2005 to assist the already existing Hispanic community in Jefferson Parish before Katrina. As of 2011, more than 15% of the parish population is Hispanic.