Northamptonshire made history by becoming the first team in their history to have their top four batsmen all score centuries, amassing 684 for two against Kent. Luke Procter led the way with a career-best 261, while Calvin Harrison added 153. Nathan McSweeney also reached three figures, hitting a six to bring up his hundred. Kent then slumped to 119 for six in reply, with Zak Crawley making 26.
At the Oval, Leicestershire defied Surrey's total of 520, with Rishi Patel scoring an unbeaten 133, his first Division One century. Jake Weatherald fell four short of a hundred, caught behind for 96, but Lewis Hill finished 60 not out as Surrey's attack toiled. Leicestershire closed on 239 for two.
Stand-in Somerset captain Craig Overton scored a career-best 141 to put his side in a dominant position at Chelmsford. He added 118 with Will Smeed, who made his first-class debut as an injury substitute three years after retiring from first-class cricket. Essex then fought back through Paul Walter and Matt Critchley, both hitting half-centuries.
At Trent Bridge, Glamorgan were bowled out for 113 as Fergus O'Neill and Brett Hutton took three wickets each. Nottinghamshire then built a lead of 450, with Joe Clarke scoring 119 not out and Ben Slater also passing fifty. Ben Duckett was run out for one.
Durham declared on 605 for five at Chester le Street, with Ben McKinney making 244, the seventh-highest score by a Durham player, and David Bedingham adding a century. Kemar Roach and Ben Raine then took three wickets each as Gloucestershire stumbled to 168 for eight.
At Old Trafford, Lancashire took only two wickets all day as Derbyshire's Brooke Guest reached fifty. Captain Harry Came fell for 83, bowled by Jimmy Anderson, whose frustration had been raised by four overthrows. Mitch Stanley impressed with an aggressive spell after lunch, removing Matthew Montgomery for 46.
