Certainly European best guess would be Belgium without any writing and even then it might be VERY difficult to identify this better. Percussion started showing up shortly after the turn of the century but I would hazard a guess that somewhere in the 1820's or 1830's based on it's design.
There were just a LOT of small gunsmiths back then making this sort of gun with no markings on them.. Value unfortunately is not a lot, I doubt you could even find a dealer that would give you more then 20 or 30 bucks for it if they would take it at all. If inherited keep if for the sentimental value