Yorkshire and Derbyshire have both been promoted to the County Championship Division One.
Their promotion was confirmed after Kent, who were also in the running to go up, lost to Glamorgan.
"It means the world, it's absolutely superb," said Derbyshire coach Karl Krikken. "I feel sorry for Kent, obviously, but it's just a great day to go up."
Derbyshire will be crowned Division Two champions if they beat Hampshire on Friday. If they fail to do so, Yorkshire can take the title with victory against Essex.