In "To Kill a Mockingbird", what is the name of the prison that Tom Robinson is being held in?
Tom Robinson is initially held in the Maycomb County jailhouse before being sent to the Enfield Prison Farm following his conviction.
In Chapter 15, Tom Robinson is being held in the Maycomb County jail before the trial takes place. The night before the trial, Atticus travels to the Maycomb jailhouse and sits out front to prevent people from attempting to harm Tom. Fortunately, Atticus and his children end up stopping the Old Sarum bunch from lynching Tom Robinson before the trial.
Following Tom Robinson's wrongful conviction, he is sent to Enfield Prison Farm, which is about seventy miles away in Chester County. In Chapter 24, Atticus interrupts Aunt Alexandra's missionary circle to take Calpurnia with him to visit Helen Robinson. Atticus proceeds to tell Alexandra, Maudie, Calpurnia, and Scout that Tom Robinson attempted to escape from Enfield Prison Farm and was shot seventeen times.
Tom Robinson is held temporarily in the Maycomb County jailhouse, and then after he is convicted, he is sent in the Enfield Prison Farm. As all of the specific places in Harper Lee's To Kill a Mockingbird are fictional, no such prison farm of the name Enfield actually exists.
A prison farm is different from a prison. Someone who is imprisoned in a prison farm is expected to partake in various manual labor tasks like logging or mining. This work earns money for the prison farm, but the prisoners do not make any money themselves. The conditions of a prison farm are similar to that of a labor camp. It is from an environment such as this one that Tom Robinson tried to escape, resulting in his death by seventeen gunshots.
The actual name of the prison is never actually given but it is mentioned a few times that he is in the county jail. Since they live in Maycomb County, the jail would most likely be called Maycomb County Jail or Maycomb County Prison.