Re: My coolest relic found here in Jackson County....
Dig's right on the money, as always!
O'Donnell & Campbell's American Military Belt Plates lists this particular "Common Militia" waist belt plate as c. 1818-1835.
There are some very similar plates dating c. 1815-1825, and of course the War of 1812 continued into early 1815. Whether any of those plates actually saw service in the last days of the war, I can't say. But again, yours is a somewhat later variety.