The 2009 County Championship season, known as the LV County Championship for sponsorship reasons, was the 110th County Championship season.
Each team played all the others in their division both home and away.
Durham County Cricket Club won the Championship for the second consecutive season.
Worcestershire and Sussex were relegated from Division One, with Kent and Essex promoted in their place.
Fourteen points were awarded for each win, four points were awarded for a draw or abandonment.