You need to have it defined as to branches in the 5 counties, or people living in the 5 counties.
Reason, the definition may be critical during a fair lending exam. A bank I was at had a similar promotion. When the pricing fair lending sample was pulled by OCC, there was a large unexplained difference, until we referred them to the exact promotion (loans by branches within the area irrespective where the applicant lived).
Integrity. With it, nothing else matters. Without it, nothing else matters.