The unit, which opened in June 1984, was named after Ward James "Jim" Estelle, a former prison director of Texas.

[8] In 1999, a prisoner named Clifford Dwayne Jones escaped by slipping one of his hands out of a pair of handcuffs and then scaling several walls.

[5] On May 12, 2010 Thord "Catfish" Dockray, a prisoner with a history of mental illness, threw urine on correctional officers.

[9] As of 2010 a study by the Bureau of Justice Statistics stated that the percentage of prisoners who were sexually abused within the preceding year was 15.7% at Estelle.

The Estelle rate was the highest in the U.S.[11] Two correctional officers secretly allowed three inmates to fight each other on April 29, 2015 and attempted to cover up the act.

The security unit also houses prisoners who purposefully cause problems in order to escape from the general population for fear of victimization.