Newton Knight (Matthew McConaughey) is a farmer in Mississippi during the Civil War. Rather than being a soldier in the Confederate Army, he chooses to be a medic, because he thinks that actually helps people. When his nephew is drafted and he asks for his help, he tries to save him to no avail. When his nephew dies in battle, a chain of events forces him to desert. He find refuge in the swamp with a group of runaway slaves. Safely hidden away, they gradually attract other deserters and farmers who have no interest in upholding a system that keeps the rights of rich people to own slaves. They secede from the Confederacy and form the Free State of Jones in the swamps of Jones County, Mississippi.

Their actions change local politics during and after the war, and have an impact far into the 20th century.

Free State of Jones is a hard movie to watch, as the cruelty against black slaves in the history of America is brought to the forefront. Racism still persists today in 2020 and watching this movie today illustrates the massive injustice that was and is being perpetrated in the name of race in the United States.