Regierungsbezirk

A Regierungsbezirk is a government region of Germany in some federal states ("Bundesländer"). 
"Regierungsbezirke" are divided into districts ("Kreise"), either "Landkreise" or urban districts: cities which constitute a district in their own right ("kreisfreie Städte"). The "Regierungsbezirk" is governed by a "Bezirksregierung" and led by a "Regierungspräsident".
Not all "Bundesländer" have this sub-division; some are directly divided into districts. Currently, five states are divided into 22 "Regierungsbezirke", ranging in population from 5,255,000 (Düsseldorf) to 1,065,000 (Gießen):
History.
The first "Regierungsbezirke" were created by the Kingdom of Prussia in 1808/16, which divided its provinces into 25 "Regierungsbezirke". The "Regierungsbezirke" of North Rhine-Westphalia are in direct continuation of those created in 1815. Other states of the German Empire created similar entities, named "Kreishauptmannschaft" (in Saxony) or "Kreis" (in Bavaria and Württemberg) (not to be confused with the "Kreis" or "Landkreis" today). During the Third Reich, the Nazi government unified the naming; since then all these entities are called "Regierungsbezirk".
On January 1 2000 Rhineland-Palatinate disbanded its three "Regierungsbezirke" Koblenz, Rheinhessen-Pfalz and Trier - the employees and assets of the three "Bezirksregierungen" were converted into three public authorities responsible for the whole state, each covering a part of the former responsibilities of the "Bezirksregierung".
On January 1, 2004, Saxony-Anhalt disbanded its three "Regierungsbezirke": Dessau, Halle and Magdeburg. The responsibilities are now covered by a "Landesverwaltungsamt" with three offices at the former seats of the "Bezirksregierungen". 
On January 1, 2005, Lower Saxony disbanded its four "Regierungsbezirke": Braunschweig, Hanover, Lüneburg, and Weser-Ems.
In 2005, North Rhine-Westphalia planned to abolish its five "Regierungsbezirke" and create three self-government entities. The old, "Prussian-style", Regierungsbezirk had no self-government organs.