Police in Prescott say the stainless-steel .38-caliber revolver was in plastic bag along with one bullet just under the ground's surface.
Police say it appears the gun was only covered up to hide it until someone came back to get it.
They say they don't know who owns the gun or how it ended up buried near the home of the boy who found it Monday. Police didn't identify the boy.
Authorities say the gun's serial number has been checked and it's not reported missing.