Tensas Parish was the home to many successive indigenous groups in the thousands of years before European settlements began.

Radiocarbon dating of charcoal found in a midden under the mound reveals that the site was occupied from 996 to 1162 during the Coles Creek period.

Historic tribes in this area were the Choctaw and Natchez, in addition to smaller groups such as the Taensa people.

Following Indian Removal by the United States government in the 1830s, the land was sold and this area was developed by European Americans for cotton plantations, the leading commodity crop before the Civil War.

Planters moved into the area from the eastern and upper South, either bringing or purchasing numerous enslaved Africans as workers.

They developed plantations along the river and Lake St. Joseph, as waterways were required for transportation routes and access to markets.

[8] But from 1878 through 1920, the Mississippi Delta area of northern Louisiana legally executed more blacks than did any other part of the state, after they had been convicted by all-white juries.

Most of the population was still engaged in cotton agriculture, where numerous African Americans worked as sharecroppers and tenant farmers.

While mechanization was gradually introduced, blacks left Tensas Parish before its full effects had taken place, to escape the violence of lynchings and executions.

These differences likely reflected a continuing outmigration by blacks, as well as in-migration of whites from other areas, who settled in the hill country during the 1920s–1930s.

[10] Both blacks and whites left the parish to move to defense industry jobs on the United States West Coast during and after World War II.

In the fall of 1964 O'Hearn was elected to an at-large seat from Caddo Parish as a state representative from Shreveport.

These new black voters were staunchly Democratic, as the national party had supported their drive for civil rights.

Some white Democrats have been elected to public offices in the parish, including Sheriff Rickey A. Jones and several school board members.

In November 2019, Alex "Chip" Watson Jr., who is African American, was elected to the District 1 police jury seat.

Although the state officially desegregated, the schools are largely de facto segregated, as many white parents have sent their children to private academies founded at that time.

[12] Historically, Tensas Parish has been heavily Democratic in orientation, although the make-up of the party has changed markedly in terms of demographics.

Louisiana as a whole narrowly cast its electoral votes for the Southern Democratic choice, Vice President John C. Breckinridge of Kentucky.

After gaining the franchise, most black men joined the Republican Party, electing candidates who made up a biracial legislature in Louisiana during Reconstruction.

In 1988, Vice President George H. W. Bush, the Republican presidential nominee, prevailed in Tensas Parish with 1,645 votes (50 percent).

[15] In 2000, the Democratic nominee, Vice President Al Gore, won Tensas Parish by 250 votes.

[19] The Obama-McCain and Obama-Romney voter divisions in 2008 and 2012 reflect the demographics of the political parties in Tensas Parish.

In the 2004 U.S. Senate primary election, Tensas Parish gave a plurality to the Republican candidate, U.S. Representative David Vitter of St. Tammany Parish, who polled 1,145 votes (41 percent) compared to 881 ballots (32 percent) for his chief Democratic rival, Congressman Chris John of Crowley.

[17] In 2007, the successful Republican gubernatorial candidate, U.S. Representative Bobby Jindal, polled 40 percent in Tensas Parish.

[20] Under the state constitution, prior to 1968, each parish -regardless of population- elected at least one member to the Louisiana House of Representatives.

Louisiana and numerous other states had not regularly conducted redistricting, although there had been dramatic population shifts since the turn of the 20th century.

Tensas Parish has one principal cemetery, Legion Memorial, established in 1943 and located just north of Newellton.

Police Jury Vice President Jane Merriett Netterville, a Democrat from St. Joseph,[22] expressed surprise at those figures, as a number of people had moved into the parish in 2005 and 2006 as refugees from New Orleans and coastal areas after Hurricane Katrina.

Netterville explained that younger people leave Tensas Parish because of the scarcity of higher-paying jobs.