State counties

http://www.poi-factory.com/taxonomy/term/15

Hope this helps

Since Custom POIs are discrete individual points, I'm not sure that a Custom POI file is what you are needing.

When riding, you might never go to the actual county seat.

If you are looking for the county boundary lines, you can load this custom map.

http://www.gpsfiledepot.com/maps/view/10/

I downloaded the map overlay, installed it, but now it says I can't unlock maps? I had that problem a little bit ago, and contacting Garmin they told me to delete a file named gmapsupp. I think this is the same file name I downloaded? Anyone have any suggestions?

Thank you,
kws

Does that allow you to search by county name, too?

Don't see any counties. I'm guessing since it won't load, I can't use the county feature.

It is this same problem like with time zones (this tread was here some time ago). As poi's marks only points you would have to mark all roads with county limits. Practically impossible to do. And having marked "capital" of county doesn't really show where county borders are.
I think at this moment only solution can be to mark counties in fashion of markings for forests or parks. But this will not alert about crossing county border and can make map less readable.
So I guess in conclusion: it can be done in limited fashion.

Thanks for info. Will delete custom file since it 'gets in way' of other files.