Sub-Level B83 is a location in HBO's Westworld TV series.
It is not at the lowest level of the Westworld Mesa Hub, because either sub-levels A or sub-levels B are below it. It is currently used to store (Cold Storage) decommissioned hosts not currently in use. It is extensive, suggesting that is was used previously for other purposes. It's also where an old host, Old Bill, is kept. Dr. Robert Ford is known to visit this level to see Old Bill.