Serial Number location?

Juts have a general question hopefully someone can answer/clarifiy for me. The Serial Number of a private aircraft would be loacted on a metal plate somewere on the aircraft just like military aircraft. My question is where would be located? on the firewall somewhere on the fuselage I'm assuming just a matter of where? I havent had to look for them really as a private pilot and not ever doing much maintenance so where should I belooking on like say a Cessna. Thanks in advance guys and gals