Essex survived a spirited comeback from Lancashire to seal a nervy win at Chelmsford, while Somerset thrashed Worcestershire.
Matt Henry took match figures of 12-73 as Kent eased to a nine-wicket victory over Durham in the County Championship.
Matt Renshaw marked his Somerset debut with an unbeaten ton as 18 wickets fell on day one of their clash with Worcestershire.
"Fresh, bold, innovative." Michael Atherton, David Lloyd and Nick Knight react to ECB's proposed 100-ball competition...
Lancashire crumbled to defeat against Nottinghamshire in their Championship opener on a morning in which 12 wickets fell.
Stuart Broad says the 100-ball concept proposed for English domestic cricket will bring a fresh tactical dimension to the game.
James Harris took nine wickets in the match as Middlesex clinched a convincing 160-run win over Northamptonshire.
Lancashire reacted well after Jake Ball fired for Notts, while 26 wickets fell in the game between Middlesex and Northants.
Will Essex retain the title? And who is in danger of sinking into Division Two? We look at the runners and riders...
With the 2018 domestic season underway , Benedict Bermange tests your knowledge of the County Championship. Good luck!
Ahead of the new county cricket season, we asked Sky Sports' David Fulton and Dominic Cork for their 2018 predictions.
England Women's Anya Shrubsole, Heather Knight and Natalie Sciver have been named in Wisden's Five Cricketers of the Year.
Jamie Porter told Sky Sports he does not need electrifying speed to make an impact for England in international cricket.
Mark Stoneman and James Vince are among six England players available for the start of the County Championship season.
Virat Kohli is set to play county cricket this summer ahead of his side's Test series against England, according to reports.
Alastair Cook admits to doubting his future, but says his double hundred in Melbourne shows he has still "got it".
New Zealand seamer Neil Wagner will be back at Essex this summer after agreeing a new contract with the county champions.
Australia leg-spinner Adam Zampa has been signed by Essex for the whole of their 2018 T20 Blast campaign.
Australia bowler Peter Siddle has joined county champions Essex for the first five games of the 2018 Championship season.
Tom Westley has been ruled out for 12 weeks due to the finger injury he sustained on England Lions duty in Australia.