| Second Largest County* | State |
| Tulsa | |
| Washoe | |
| Washington (County Seat: Hillsboro) | |
| Ramsey | |
| Dona Ana | |
| Pennington | |
| De Kalb | |
| Pima | |
| Lake | |
| Natrona | |
| Hartford | |
| Jackson | |
| Burleight | |
| Allegheny | |
| Hawaii | |
| Harrison | |
| Mobile | |
| Wake | |
| Canyon | |
| York | |
| Johnson | |
| Jefferson (County Seat: Golden) | |
| Essex | |
| Jefferson (County Seat: Gretna) | |
| Suffolk | |
| | Second Largest County* | State |
| Du Page | |
| Franklin | |
| Dane | |
| Linn | |
| Dallas | |
| Richland | |
| Utah | |
| Washington (County Seat: Fayetteville) | |
| Fairbanks North Star | |
| Kent | |
| Rockingham | |
| Lancaster | |
| Cabell | |
| Pierce | |
| Fayette | |
| Davidson | |
| Broward | |
| Prince William | |
| Norfolk | |
| Oakland | |
| Rutland | |
| Prince George's | |
| Cascade | |
| Orange | |
| Sussex | |
|