The Hess and Hesse surnames are most prevalent in Germany.  While they are most closely associated with the current German state of Hessen and its medieval predecessors, the names are found throughout Germany and into neighboring countries.

According to the Geogen website (http://geogen.stoepel.net/index.html) Hess is the 124^th ranked surname in Germany.  It is most commonly found in the southwestern regions, mostly in the states of Baden-Wuerttemburg, Rhineland-Palatinate, Saarland, Hesse, Thuringia and northwest Bavaria.  Hesse ranks 160^th and is found in a band from the Rhine River near Dusseldorf eastwards to the area bordering Poland and the Czech Republic, concentrated in North Rhein-Westphalia, Hesse, Thuringia, Lower Saxony, Saxony-Anhalt and Saxony.  Other surnames fall outside the top 1000 surnames in Germany, but can be researched on the Geogen website.