Please help me find my adult son. His name is <removed for privacy and safety>. Last know address was a PO box in Big Piney Wyoming. I have written to this PO box but
Get no return answers but my letters are not returned. <removed for privacy and safety>.
He has lived in the Portland OR area and the state of Washington. His mother changed his last name just before she died of cancer and turned him and his older brother against me. I always paid child support and she did everything so I could not visit with them when they were children, moving 1200 miles away and me a working man. I am heartbroken, can you help me?

Best start is Facebook - by his name, and the name of his town.
Given that the PO is obligated by law to return mail that is undeliverable, it sounds like he's getting your mail though.
I found a restaurant called the Krazy Moose there, so get the number and call them.

Please do not post identifying information for yourself or others. It isn't safe you or them to post full names and dates of birth on public websites.

We can give you tips on trying to find your son. However, we do not actually search for people.

Have you tried Facebook or other social websites?

Are there any family members or friends she kept in touch with who might know his whereabouts?

I'm having a bit of a problem with this. She didn't let you be a part of their lives? Why didn't you fight for your rights? So you're a working man, most men are, and women too.

Yes it's hard, but you had options, and it doesn't seem that you took those options.

It sounds like he's getting the mail, since it's not being returned. Sounds like he's giving you a clear message that after all this time, when you didn't fight for him at all, he no longer wants any contact. You have to respect that.

Sorry if that's harsh, but the truth often is. :(

So, take a few weeks off work, travel there and look for him?