How can you determine where a letter was mailed from with no return address & only a partial postal stamp?

I received an "anonymous" letter and all I can read on the envelope is the city and date. Can it be tracked down?How can you determine where a letter was mailed from with no return address %26amp; only a partial postal stamp?
Sometimes... If it is a threatening letter the inspection service can sometimes use the pink barcode on the back to see where it was barcoded and if it were a matter of national securiety the can look at the addresses that went in before and after that letter and track it down to the city where it was dropped off. Usually the city is where it is postmarked.How can you determine where a letter was mailed from with no return address %26amp; only a partial postal stamp?
You can't.How can you determine where a letter was mailed from with no return address %26amp; only a partial postal stamp?
No. Although the letter was scanned when it was received at a central posting station, there will be no direct record of which carrier picked it up and where. Depending on the City name, you could identify what City and State but that's as far as you'll get.