At this time, the total population of the county numbered about 4000 people, about 80% of whom were middle-class families of seventeenth-century Virginia stock who had gradually migrated through other frontier states.

The county economy was based on timber from longleaf pine and the cultivation of commodity crops of cotton, indigo, and tobacco, usually on plantations worked by enslaved African Americans.

Given the reliance of planters on labor-intensive crops such as tobacco and cotton, the county soon had a majority population of enslaved African Americans.

In the 1850s, Liberty hosted opera singer Jenny Lind, known as the "Swedish Nightingale," at the Walsh building.

[5] After Reconstruction, white Democrats regained power in the state legislature through a combination of violent voter repression and fraud.

[5] The county had 14 documented lynchings in the period from 1877 to 1950; most took place around the turn of the century when disenfranchisement and imposition of Jim Crow was underway.

As agriculture was mechanized, reducing the need for farm labor, many blacks left Amite County during the first half of the 20th century in two waves of the Great Migration.

Steptoe founded a chapter of the National Association for the Advancement of Colored People (NAACP) in the county.

In the summer of 1961, Bob Moses from the Student Nonviolent Coordinating Committee worked in the county to organize African Americans for voter registration.

Even after the Voting Rights Act was passed in 1965, extensive grassroots efforts were required to register eligible voters.

At the inquest that day, Hurst claimed self-defense and witnesses, intimidated by the armed white men in the courtroom, supported him.

Learning that the federal government might hold a grand jury in the case, Louis Allen, an African-American veteran of World War II and witness to Lee's murder, talked to the FBI to try to gain protection if he were to testify truthfully to what he saw.

African Americans did not register until after passage of the Voting Rights Act of 1965, which provided federal protection and oversight.

[citation needed] On October 20, 1977, a rental plane carrying members of the band Lynyrd Skynyrd from Greenville, South Carolina, to LSU in Baton Rouge, Louisiana, was low on fuel and crashed in a swamp in Amite County.

[13][14] As mechanization of agriculture decreased the need for farm labor, the population has dropped since its peak in 1910 at 22,954, as people left in search of work in other areas.

In the early part of the 20th century, particularly from 1910 to 1930, and from 1940 to 1970, it was affected by the Great Migration of blacks out of the segregated society for jobs and opportunities in Midwest and later, West Coast cities.

Particularly in the early 20th century, Blacks left to escape the oppression and violence associated with Jim Crow, lynchings, and their disenfranchisement after 1890.

Rural whites also left in those years, but a much greater number of African Americans migrated to other areas.

In 2020, its racial/ethnic makeup was 58.44% non-Hispanic white, 38.01% Black or African, 0.2% Native American, 0.24% Asian, 2.09% other or multicultural, 1.01% Hispanic or Latino (of any race).