The Gewwwlakh, a state run farm in former Kassadinian lands was the location that all criminals in Rewbokh territory go for life after they've been convicted of a major crime.

But how are they convicted?

The local ruler, no matter what level they are (Mayor, Vassal Viceroy, and Viceroy) will convict them. Depending where the convict is captured (not where the committed the crime) depends on how they are put on trial. In the south there tends to be a small trial with people coming to show facts supporting the positions in the case while in the north the ruler will decided by themselves on the punishment.

What is considered a 'major crime'?

Just like the trial, a major crime is determined by the ruler. Some places a major crime can be stealing a cart/horse/cow, others places rape isn't even considered a major crime.

What does the Gewwwlakh look like?

As said, the Gewwwlakh is a state-run farm in the Kassadinian mountains. The walled facility is constantly guarded by members of the Deathguard and is (supposed to be) fully independent and self-contained. Because of this, there is little oversight on daily operations and gangs run the sight.

What about 'minor crimes'?

Minor crimes tend to just have to pay a fine for the action, but other punishment can be dealt (like in The Monastery where stealing food means cooking for that person for a month.)