Washington State: Any number of hives above zero have to be registered. 1-5 hives is $5.00 total for the year. It's a sliding scale, 1,001 or more hives is $300 per year. Expensive fine if you don't register. You also have to indicate if you'll be using them for commercial pollination, but no extra fees for that.
Certain cities have stricter requirements as to how many hives you can have, where they can be placed, etc. I've not yet stumbled upon county level requirements.
(IMHO, this is primarily a small revenue generator/department justifier. You get a newsletter out of it. GPS Locations of all hives? You gotta be kidding me. I'd give them GPS coordinates, all righty.)