2020 census
As of the 2020 United States census, there were 21,107 people, 7,582 households, and 4,899 families residing in the parish.
2000 census
As of the census of 2000, there were 22,803 people, 8,857 households, and 6,412 families residing in the parish. The population density was 26 people per square mile (10/km2). There were 10,873 housing units at an average density of 12 per square mile (5/km2). The racial makeup of the parish was 69.79% White, 27.95% Black or African American, 0.19% Native American, 0.26% Asian, 0.05% Pacific Islander, 1.26% from other races, and 0.50% from two or more races. 2.02% of the population were Hispanic or Latino of any race.
There were 8,857 households, out of which 31.30% had children under the age of 18 living with them, 55.30% were married couples living together, 13.70% had a female householder with no husband present, and 27.60% were non-families. 24.90% of all households were made up of individuals, and 11.00% had someone living alone who was 65 years of age or older. The average household size was 2.52 and the average family size was 3.01.
In the parish the population was spread out, with 25.70% under the age of 18, 9.10% from 18 to 24, 26.50% from 25 to 44, 23.80% from 45 to 64, and 14.90% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 94.50 males. For every 100 females age 18 and over, there were 90.90 males.
The median income for a household in the parish was $29,061, and median income of a family was $36,035. Males had a median income of $30,494 versus $21,070 for females. The per capita income for the parish was $14,819. About 14.30% of families and 18.60% of the population were below the poverty line, including 25.60% of those under age 18 and 17.70% of those age 65 or over.
Politics
Located in far northern Louisiana next to the Arkansas state line, Union Parish is heavily Republican in most competitive elections, particularly at the presidential level, last voting for a Democratic presidential nominee in 1952 when Adlai Stevenson received 52% of the vote. In the most recent election in 2020, incumbent President Donald Trump received 8,407 votes (75.1 percent) of the parish total to 2,654 (23.7 percent) for former Vice President Joe Biden.
Education
Residents are assigned to Union Parish Public Schools.
Border monument
In 1931, a monument was erected at the Union Parish border with Union County, Arkansas, through the private efforts of former Arkansas Governor George Washington Donaghey, who felt attached to both states. The monument is known for its intricate carvings and Art Deco style. The land was not registered with the state parks offices in either state, and the monument was eventually forgotten. In 1975, State Representative Louise B. Johnson passed a law to refurbish the monument. The completed restoration was unveiled in 2009.
Communities
thumb|250px|Map of Union Parish, Louisiana With Municipal Labels
Towns
Bernice
Farmerville (parish seat and largest municipality)
Marion
Villages
Conway
Downsville
Junction City
Lillie
Spearsville
Unincorporated communities
Alabama Landing
Ouachita City
Point
Shiloh
Notable people
Two Louisiana governors came from the Shiloh Community in Union Parish:
William Wright Heard, 1900–1904
Ruffin Pleasant, 1916-1920
Two Arkansas governors were natives of Union Parish:
George Washington Donaghey, Governor of Arkansas from 1909 to 1913
Tom Jefferson Terral, Governor of Arkansas from 1925 to 1927
Other Union Parish residents have included:
Lonnie O. Aulds (1925-1984), state representative from 1968 to 1972 from Shreveport, real estate developer, born in Union Parish
George Washington Bolton (1841-1931), state representative from 1888 to 1896 from Alexandria; Speaker of the House from 1892 to 1896; businessman, banker, school board member, Southern Baptist layman in Alexandria, lived and educated in Union Parish in his father's private school prior to the American Civil War
Harvey Fields, state senator from 1916 to 1920, member of the Louisiana Public Service Commission from 1927 to 1936, briefly a law partner of Huey Pierce Long, Jr., in Shreveport. His son, T. T. Fields, served in the Louisiana House of Representatives from 1952 to 1964 and 1968 to 1972.
Jay McCallum - Chief Judge of the Louisiana 3rd Judicial District Court (elected in 2003); ran unopposed in 2014 for a term ending in 2020; state representative for Lincoln and Union parishes, 1992–2003; formerly practiced law in Farmerville after graduating from Louisiana State University School of Law in 1985
B. R. Patton (1920-1999), state senator for Lincoln and Union parishes, 1956 to 1964; worked on the establishment of Lake D'Arbonne at Farmerville
Robert Roberts, Jr., born in Union Parish in 1872, mayor of Farmerville c. 1900, mayor of Minden 1905–1906, state representative for Webster Parish 1908–1914, and state district judge 1920 to 1925
James Peyton Smith (1925-2006), born in the Conway Community in Union Parish; state representative from Union and Morehouse parishes from 1964 to 1972; namesake of Louisiana Highway 33 bridge over Lake D'Arbonne in Farmerville
Lee Emmett Thomas, born in Marion in Union Parish, and educated as a child in the Shiloh Community at the former Concord Institute. He was mayor of Shreveport (1922–1930) and Speaker of the Louisiana House of Representative (1912–1916). Thomas also served by appointment in both the Heard and Pleasant administrations.
