Nottinghamshire won the County Championship on the final day of last season
Nottinghamshire will begin the defence of their County Championship title at home to Hampshire on 14 April.
The champions open the season with the traditional game against the MCC, which is again being held in Abu Dhabi, with the Championship beginning on 8 April.
Next year may be the last Championship played by two divisions of nine teams, as counties are likely to opt for an eight-team top flight in 2012.
The CB 40 begins on 24 April, with the FP t20 getting under way on 1 June.
Defending CB 40 champions Warwickshire begin their quest to retain the trophy away at Hampshire, while beaten finalists Somerset are at Notts.
In the FP t20, which is again split into two geographical groups of nine teams for the early stages, holders Hampshire welcome Somerset to The Rose Bowl on the opening day in a repeat of last season's final.
The final of the CB 40 will be held at Lord's on 17 September, while FP t20 finals day will take place at Edgbaston on 27 August.
After Notts open the first-class season against the MCC on 27 March, several counties will warm-up for the new campaign against university sides on 2 April.
The opening round of Championship fixtures sees Division Two champions Sussex return to the top flight with a trip to Lancashire, while elsewhere in Division One, promoted Worcestershire host Yorkshire and Durham make the long trip to Hampshire.
In the second tier, relegated pair Essex and Kent meet at Chelmsford, while Leicestershire entertain Glamorgan, Derbyshire travel to Gloucestershire and Surrey welcome Northants.
On their return from Abu Dhabi, Notts get their campaign under way in the second round of matches, which is when last season's runners-up Somerset begin their season by hosting Warwickshire.
The summer schedule also includes fixtures against touring sides Sri Lanka, India and India A, with the final round of County Championship matches beginning on 12 September.
FRIENDS PROVIDENT T20
Northern division: Derbyshire, Durham, Lancashire, Leicestershire, Northants, Nottinghamshire, Warwickshire, Worcestershire, Yorkshire
Southern division: Essex, Glamorgan, Gloucestershire, Hampshire, Kent, Middlesex, Somerset, Surrey, Sussex
CLYDESDALE BANK 40
Group A: Derbyshire, Middlesex, Worcestershire, Sussex, Yorkshire, Kent, Netherlands.
Group B: Hampshire, Durham, Northants, Warwickshire, Surrey, Leicestershire, Scotland.
Group C: Nottinghamshire, Glamorgan, Gloucestershire, Essex, Somerset, Lancashire, Unicorns.