All the VA medical centers have federal police officers. If you frequent there you can get an idea by seeing what antenna are on their portables. Some are VHF Federal (162-174) and some are UHF Federal (406-420).
Some do use local trunk systems however in certain areas.
From the ColdWarComms Group. There is a classified section which (for obvious reasons) is not included. It's a huge document, over 15k pages. (You can view it from the link without downloading it, though.) https://www.governmentattic.org/41docs/NTIAgovtMasterFile_2021.pdf
Is the thread, keep in mind the PDF is rather large, but you can just search on Tuscal and will find some [Not all are listed, such as the PD]
of the potential targets to enter, but you are still best to SEARCH as there are plenty that were not released