They're generally listed where they're licensed. That doesn't mean they're being used, however. It probably means that it's available to them.
South of the border in Georgia, virtually every county has access to a pair of frequencies that have been used for probably 50 years or more. Many smaller counties used them for dispatch, to talk to neighboring counties and to talk with the State Patrol. As time progressed, counties got their own frequencies but they still had (and have) access to that pair of frequencies.