I know Guest Creek Lake had a posting of length limit of 22'. I had a 25' pontoon and I used it on GC and no one ever measured my boat, guess I got lucky.

The main thing is to not confuse state run lakes in KY with lakes run by the Army Corp of Enginers in KY. Most of the state run lakes will be smaller lakes and I guess that the reason for the length/HP restrictions. But this does not mean you cannot use a bigger boat in KY. There are a lot of ACE lakes in KY without length or HP restrictions.