2020 census
As of the 2020 United States census, there were 18,687 people, 7,162 households, and 4,562 families residing in the parish.
2000 census
As of the census of 2000, there were 20,247 people, 7,521 households, and 5,430 families residing in the parish. The population density was 29 people per square mile (11/km2). There were 9,148 housing units at an average density of 13 per square mile (5/km2). The racial makeup of the parish was 57.9% White, 40.7% Black or African American, 0.16% Native American, 0.3% Asian, 0.55% from other races, and 0.8% from two or more races. 1.2% of the population were Hispanic or Latino of any race.
There were 7,521 households, out of which 33.00% had children under the age of 18 living with them, 49.00% were married couples living together, 19.00% had a female householder with no husband present, and 27.80% were non-families. 25.30% of all households were made up of individuals, and 11.50% had someone living alone who was 65 years of age or older. The average household size was 2.60 and the average family size was 3.12.
In the parish the population was spread out, with 27.80% under the age of 18, 8.90% from 18 to 24, 25.60% from 25 to 44, 23.00% from 45 to 64, and 14.70% who were 65 years of age or older. The median age was 37 years. For every 100 females, there were 95.20 males. For every 100 females age 18 and over, there were 91.90 males.
The median income for a household in the parish was $22,742, and the median income for a family was $28,629. Males had a median income of $27,453 versus $18,678 for females. The per capita income for the parish was $11,966. About 24.30% of families and 29.10% of the population were below the poverty line, including 42.00% of those under age 18 and 20.60% of those age 65 or over.
Education
Concordia Parish School Board operates public schools in the parish.
National Guard
1086TH Transportation Company of the 165TH CSS (Combat Service Support) Battalion of the 139TH RSG (Regional Support Group) is based in Vidalia, Louisiana on the west bank of the Mississippi River.
Communities
City
Vidalia (parish seat and largest municipality)
Towns
Ferriday
Clayton
Ridgecrest
thumb|200px|Map of Concordia Parish, with municipal labels
Census-designated places
Minorca
Monterey
Spokane
Other unincorporated communities
Acme
Ashland
Black Hawk
Eva
Fairview
West Ferriday
Notable people
Arts and entertainment
Jerry Lee Lewis, musician
Jimmy Swaggart, televangelist
Mickey Gilley, musician
Journalism
Campbell Brown, Emmy-award-winning journalist, CNN Anchor/host.
Sam Hanna, Sr., late publisher of Concordia Sentinel in Ferriday
Howard K. Smith, ABC and CBS commentator
Politics
Al Ater, State representative (1984–1988) and secretary of state (2005–2006)
Leo Boothe, longest-serving District Judge of Concordia Parish and Catahoula Parish (1991−2015)
Clifford Cleveland Brooks, planter in St. Joseph, represented Concordia Parish in the Louisiana State Senate from 1924 to 1932.
James H. "Jim" Brown, state senator (1972–1980), Louisiana secretary of state (1980–1988), and insurance commissioner (1992–2000)
Charles C. Cordill, Louisiana state senator representing Concordia and Tensas parishes from 1884 to 1912
Noah W. Cross, Concordia Parish sheriff, 1944−1948; 1952−1973
Brenham C. Crothers, Ferriday cattleman; state senator from delta parishes from 1948 to 1952 and 1956−1960
Troyce Guice, U.S. Senate candidate, 1966 and 1986
Bryant Hammett, state representative, 1992–2006
Shelby M. Jackson, Education superintendent, 1948–1964
Consuelo Montagu, Duchess of Manchester (1858−1909), spent part of her childhood at Ravenswood Place plantation, in the vicinity of Lake St. John.
Ed Rand, late state representative (1960−1964) from Rapides Parish had a second home on Lake St. John.
Dan Richey, state senator, 1980–1984
Fred L. Schiele, state representative (1964−1968), Concordia Parish sheriff (1973−1980)
J. Robert Wooley, state insurance commissioner (2000−2006); practiced law in Concordia Parish with James H. "Jim" Brown in late 1970s
