The Blues full-back, who's contract at St. Andrews was due to expire in the summer has joined the Rams on a two-year contract.
Kenna was one of manager Steve Bruce's first signings when he took over the mangers role at St. Andrews just over two years ago. He went on to make 80 starts for the Blues after signing from Blackburn having at first been on loan.
Kenna played a big part in helping Blues back to the top-flight two seasons ago and we at Singing The Blues wish him well in his future at Pride Park.