@Teabill,
It's not very-narrow FM. Just plain vanilla narrow-FM. Any scanner capable of receiving P25 will have an option for narrow FM reception.
Also, the adjacent counties use a NAC of 179. When they were all analog, wideband FM they shared a CTCSS (or PL) tone of 179.9. Try loading the NAC 179 into your scanner with their frequency.
Also, many scanners allow for NAC search. Program another channel with 159.210 NFM and NAC search (or whatever it is called in your scanner).
Double-check your antenna. All good with it? Are you close to the Sheriff's office? Might be busier at shift change (6am, 7am, 8am, 6pm, 7pm, 8pm) when officers sign in/off the radio.
Good luck (and report back),