| Administrator(s) | England and Wales Cricket Board |
|---|---|
| Cricket format | First-class cricket (4 days) |
| Tournament format(s) | League system |
| Champions | Nottinghamshire (5th title) |
| Participants | 18 |
| Matches | 144 |
| Most runs | Ed Joyce (1,668 for Middlesex)[1] |
| Most wickets | Mushtaq Ahmed (80 for Sussex)[2] |
The 2005 County Championship season, known as the Frizzell County Championship for sponsorship reasons, was contested through two divisions: Division One and Division Two. Each team played all the others in their division both home and away. The top three teams from Division Two were promoted to the first division for 2006, while the bottom three sides from Division 1 were relegated.