This polygon layer shows the Bezirke (in German) or "Boroughs" of Berlin as of 2001. Since a 2001 administrative reform, Berlin is made up of twelve boroughs (German: Bezirke), each with its own local government, though all boroughs are subject to Berlin’s city and state government.
After reunification in 1990, Berlin consisted of 23 boroughs. A constitutional amendment passed by the House of Representatives in 1998 set the parameters for borough reform, which went into effect at the beginning of 2001 and reduced the number of boroughs to twelve. Only the three largest boroughs, Neukölln, Reinickendorf, and Spandau, were unchanged by the reform. The others were combined into larger administrative units, although the original borders were retained. At the same time, the new borough structure achieves a certain balance in terms of population size.
Each borough is governed by a council (Bezirksamt) with five councillors (Bezirksstadträte) and a borough mayor (Bezirksbürgermeister).