The English domestic structure changed this season.
First Class
The First-Class (4 day) is the same (other than Northants and Lancashire swapped divisions with Surrey and Derbyshire).
County Championship Div 1: Durham, Lancashire, Middlesex, Northants, Nottinghamshire, Somerset, Sussex, Warwickshire and Yorkshire
County Championship Div 2: Derbyshire, Essex, Glamorgan, Gloucestershire, Hampshire, Kent, Leicestershire, Surrey and Worcestershire
List A
The big changes have occurred in the limited overs competitions. The YB40 (40 overs) is now the Royal London One-Day Cup (now 50 overs). Unicorns, Scotland and Netherlands are no longer included. I believe the divisions were picked randomly. 8 games per team (4 home, 4 away), therefore you play every team once.
Royal London One-Day Cup Group A: Derbyshire, Essex, Gloucestershire, Hampshire, Lancashire, Leicestershire, Northamptonshire, Worcestershire and Yorkshire
Royal London One-Day Cup Group B: Durham, Glamorgan, Kent, Middlesex, Nottinghamshire, Somerset, Surrey, Sussex and Warwickshire
Twenty20
The FLt20 has re-branded and is now the T20 Blast, and only has 2 regional divisions. Strangely each team plays all but one team twice (home and away) the other side (usually the furthest away) you only play once.
Natwest T20 Blast North Group: Birmingham (formerly Warwickshire), Derbyshire, Durham, Lancashire, Leicestershire, Northamptonshire, Nottinghamshire, Worcestershire and Yorkshire
Natwest T20 Blast South Group: Essex, Glamorgan, Gloucestershire, Hampshire, Kent, Middlesex, Somerset, Surrey and Sussex
Hope that all made sense!