Is it hollow or solid, Most cannonballs are more of iron, but there are some made of lead. Maybe some of the other members can chime in on this.
Update: After seeing Jeff of PA's post about it may being a War of 1812 cannon, I think that he may have got it, it looks a lot like the one pictured. Good luck I hope it is a War of 1812 cannonball!
Coinman123,