Not being from the area [only a tourist[ many of the USFS and NPS are in the middle of changing frequencies to confirm to the NTIA input/output standards.
Others are also moving from Analog to P25
I would say, put a radio into Search mode and search 162-174 Mhz at 12.5 Khz
Ben, I'm still hearing Fredericksburg and Spotsylvania Battlefield park rangers and Shenandoah National Park. The Fredericksburg/Spotsylvania channel isn't very active, but I do hear the rangers go on/off duty and the occasional traffic stop.
I don't know what is going on up here. I am in Fredericksburg area. I get some of the Fredburg area rangers. But nothing else on NPS. I reloaded the list twice. Using the same 536 hooked to the same good Diamond discone with a 10db preamp. Everything else is working AOK. Weird.