Could it be an old dog tag?
I was thinking the same thing but the old dog tag's normally have the city or county name on them.
Even though there is no city I think that its a dog tag because the ring hole is wore through. Those old dog tags wore through eventually because the dog jumped around so much.
Could it be an old dog tag?
On the similar one at the link below it is said to be “Mayor & City Council” of Baltimore Md.
http://www.treasurenet.com/forums/tokens-tags/499134-dog-tool-tags-1853-farmhouse.html