It has been a long time since I did this, and things might have changed with the newer cart software.

All I need is an extra field on the registration page for customers in a certain state (only one) to enter the county in which they reside for us to calculate taxes.
Note: *** If you live in the state of Ohio, please enter the county you reside in.***

we already have the field in the address book... entry_county

Any help is appreciated.

zen cart 1.3.6