Skimmed through my book "Media of Exchange Used in State and Federal Penitentiaries", but did not see a "Newgate Prison" listed (no index of prisons). But I am tired, so could have easily missed it if it were there. Is it from the U.S.? If so, a state or some other location identifier would be most helpful, as would a picture.
Don't know for sure but this may help. It is a page on Simsbury, in the State of Connecticut discussing caverns and buildings named "Newgate Prison". http://www.coinfacts.com/historical_notes/history_of_the_higley_copper_coins.htm
