Stahlhut is a German name.  It is a nickname for a soldier who wore a metal helmet, from Middle High German stalhuot, 'steel helmet.'  (Dictionary of American Family Names)

My Stahlhut family came from Meerbeck, which is located in Niedersachsen, or Lower Saxony.  The pictures below show the Lutheran Church in Meerbeck where the Stahlhut family worshipped.