These are issued to county officers and use the standard county prefixes.
These were first issued on the 1979 blue base.
WHAT THE LETTERS MEAN
The first letter is the county code, and the stacked letters are generally the initials of the person the plates are issued to.
However, the officer can choose alternate letters if they want, or if their initials have already been issued in their county.
(Thanks to JT for this information.)
WHAT THE NUMBERS MEAN
The single digit on the county officer plates indicates the type of officer the plate is registered to.
Numbers 1 through 3 are for elected county officials.
Numbers 4 through 9 are for non-elected (appointed) county officials.
(Thanks to Paul Rosenberg for this information.)
Naturally, as people will pick the lowest number available, we have more 1's and 4's than anything else.
Car numbers are allowed here as well; I have only seen -2, indicating a second car.
The numbers 1 through 3 are reserved for elected county officers.
Should be "COUNTY OFFICER"
The numbers 4 through 9 are reserved for non-elected (appointed) county officers.
Most of the COUNTY OFFICER plates on the roads use "4", as this is the lowest number available.
Flat county officer plates started appearing in 2015.
Should be OFFICER not CLERK
This is the corrected plate
Same plate with user-supplied map