Based on my understanding of TCA, here is what I gather on TN Knife Law. Knives <= 4" are acceptable to carry in public. Knives > 4" are acceptable if they are incidental to other activities such as outdoor recreation (backpacking knives). Fixed blades and folding knives are both acceptable. Switchblade knives are illegal to carry unless you are qualified law enforcement or EMS. Note that knives like the Kershaw Speedsafe are not considered switchblade knives even though they are spring assisted since you have to actually press on a portion of the blade (not a button) to open the blade.