No specific law on length in Ohio from what I've found but other states do have length limits http://thefiringline.com/library/blades/knifelaws.html... our CHL instructor told us Ohio has laws against carrying deadly weapon so if you do carry a knife and are ever stopped and searched it is a tool used for opening boxes, cutting string, cleaning your finger nails, slicing apples anything other than weapon Ohio does not classify a normal (non switchblade or butterfly) knife as deadly weapon until the person carrying it uses it as one.