The longest freshwater shark on record was found in Deep Creek Lake in the western panhandle of Maryland in 1983. It measured 9 feet 4 inches in length and weighed 512 pounds. The only other freshwater shark over 8 feet in length was found in Lake Cumberland, Kentucky in 2001. It was 8 feet 7 inches long and weighed 428 pounds and was thought to be responsible for all 3 shark attacks in that lake that summer.
I just did a quick search of the KDFWR's website. Didn't find anything mentioned about freshwater sharks at all. The only mention I saw was when they said freshwater sturgeons have a "shark-like" body.