Since most county jails have no reason to communicate outside the jail their radios operate in simplex, that is by not going through a repeater. Basically handheld radio to handheld radio or maybe handheld to base radio. You would have to be very close to the jail to hear these transmissions.
I don't see any jail/corrections talk groups on the 800 system page.
The jail does use a low power repeater. They do not have a simplex channel because the signal would not penetrate through all the cement and steel.
The jail uses both channels listed in the database. Channel 1 is quite busy, and channel 2 is used for longer transmissions that won't tie up the main channel. The jail is still using their UHF HT1000 portables for normal operations, but have several XTS5000's should they need to be in contact with someone on the Summit 800 system.