Off market owner phone numbers

[Nate Williams]

When looking at off market deals, I have an app that tells me the owner, acreage, property lines, and tax address (basically like a GIS map). Usually, I'll google the owner and see if I can find their number, but often times I can't. How are you guys finding the phone numbers of these property owners when looking for leads on off market deals? Is there a way to consistently get phone numbers from these property owners, or should I just be sending letters to the tax address?