It was named Farm-Raised Catfish Capital of the World in 1976 by then Governor Cliff Finch, since it produces more farm-raised catfish than any other U.S. county. 40,000 acres (160 km²) of the county are underwater, used to grow catfish. About 60 % of U.S. farm-raised catfish are grown within a 65 mile (105 km) radius of the county seat, Belzoni. However, the title "Catfish Capital" has also been claimed by Savannah, Tennessee, and Des Allemands, Louisiana.
As of the census of 2000, there were 11,206 people, 3,765 households, and 2,695 families residing in the county. The population density was 27 people per square mile (10/km²). There were 4,138 housing units at an average density of 10 per square mile (4/km²). The racial makeup of the county was 27.17% White, 71.51% Black or African American, 0.10% Native American, 0.27% Asian, 0.64% from other races, and 0.31% from two or more races. 1.50% of the population were Hispanic or Latino of any race.
There were 3,765 households out of which 36.60% had children under the age of 18 living with them, 38.30% were married couples living together, 27.70% had a female householder with no husband present, and 28.40% were non-families. 24.90% of all households were made up of individuals and 10.90% had someone living alone who was 65 years of age or older. The average household size was 2.95 and the average family size was 3.54.
In the county the population was spread out with 32.70% under the age of 18, 10.70% from 18 to 24, 25.80% from 25 to 44, 18.80% from 45 to 64, and 12.00% who were 65 years of age or older. The median age was 30 years. For every 100 females there were 87.50 males. For every 100 females age 18 and over, there were 78.70 males.
The median income for a household in the county was $20,566, and the median income for a family was $23,719. Males had a median income of $24,948 versus $19,201 for females. The per capita income for the county was $10,926. About 32.40% of families and 38.20% of the population were below the poverty line, including 50.30% of those under age 18 and 31.00% of those age 65 or over.