Yellow Letter returns

[David Gagne]

I get very excited when I'm out driving for dollars and find a vacant home.  I then come home,search county tax records and find the mailing address for the property I spotted is the same as the property address.  How can this be ?where should I mail the letter to?  When I do send to the property address it comes back saying "return to sender vacant unable to forward". 

Any ideas on where to locate where I should mail it too?