It took place between June and August, with 38 teams taking part: 34 county teams, alongside Scotland, Ireland, Wales and Netherlands.
Sussex Women won the Twenty20 Cup, achieving their second title.
The tournament ran alongside the 50-over 2015 Women's County Championship.
[1] Teams played matches within a series of divisions with the winners of the top division being crowned the Champions.
The top team in each Division Four group progressed to a final group of three, with the top two being promoted.