To be honest, I've never been in or to one (with the exception of a tour of Alcatraz Island). I also have very little experience with the judicial system outside of watching 'crime procedure' shows on TV. I mean, I know generally what the functions of each are, but how they operate and what the differences in how they operate are is knowledge I just haven't needed. The best I can do is ask around on this end. Otherwise, the only thing I can think of is that you might check the website for the state your story would be set in or maybe the Bureau of Prisons website?