| | Adams County | OH | 39001 | | | | | not in metro; pop <
5k; metro-adjacent | nonspecialized | https://maps.google.com/?q=AdamsCounty+OH |
| | Allen County | OH | 39003 | | Lima, OH 30620 | Lima-Van Wert-Celina, OH 338 | Central | in metro of < 250k | nonspecialized | https://maps.google.com/?q=AllenCounty+OH |
| | Ashland County | OH | 39005 | | Ashland, OH 11740 | Mansfield-Ashland-Bucyrus,
OH 360 | Central | not in metro; pop > 5k
< 20k; metro-adjacent | nonspecialized | https://maps.google.com/?q=AshlandCounty+OH |
| | Ashtabula County | OH | 39007 | | Cleveland, OH 17410 | Cleveland-Akron-Canton,
OH 184 | Outlying | in metro of > 1m | manufacturing-dependent | https://maps.google.com/?q=AshtabulaCounty+Ohio |
| | Athens County | OH | 39009 | | Athens, OH 11900 | Columbus-Marion-Zanesville,
OH 198 | Central | not in metro; pop
>20k; metro-adjacent | federal/state
government-dependent | https://maps.google.com/?q=AthensCounty+OH |
| | Auglaize County | OH | 39011 | | Wapakoneta, OH 47540 | Lima-Van Wert-Celina, OH 338 | Central | not in metro; pop
>20k; metro-adjacent | manufacturing-dependent | https://maps.google.com/?q=AuglaizeCounty+OH |
| | Belmont County | OH | 39013 | | Wheeling, WV-OH 48540 | | Central | in metro of < 250k | mining-dependent | https://maps.google.com/?q=BelmontCounty+OH |
| | Brown County | OH | 39015 | | Cincinnati, OH-KY-IN 17140 | Cincinnati-Wilmington,
OH-KY-IN 178 | Outlying | in metro of > 1m | nonspecialized | https://maps.google.com/?q=BrownCounty+OH |
| | Butler County | OH | 39017 | | Cincinnati, OH-KY-IN 17140 | Cincinnati-Wilmington,
OH-KY-IN 178 | Central | in metro of > 1m | nonspecialized | https://maps.google.com/?q=ButlerCounty+OH |
| | Carroll County | OH | 39019 | | Canton-Massillon, OH 15940 | Cleveland-Akron-Canton,
OH 184 | Outlying | in metro of > 250k
< 1m | nonspecialized | https://maps.google.com/?q=CarrollCounty+OH |