I originally listed the districts as secondary subdivisions. The situation in 1999 was that eight states were divided into districts. I treated the other eight as district equivalents at level 04 krefeld secondary level. Since then, more and more districts have been consolidating.

I’ve decided that it makes more sense to treat the counties as secondary subdivisions. Typ: See list of subdivision types below. This is the list of the 40 administrative districts as of 1999, the post-reunification peak. Since then, they have been consolidated one step at a time, and their administration has been conducted at the state level. Rb: Arbitrary code, key to list above. Land: HASC code for the state containing this district.

As of 2014: Present-day Regierungsbezirk for this district. 2001-11-01: Hannover rural district and Hannover urban county merged to form Hannover region. Aachen Kreis, which was dissolved, and whose nine Gemeinden with the kreisfreie Stadt of Aachen form the new city region. 2011-08-01: Name of Soltau-Fallingbostel rural district changed to Heidekreis. 2011-09-04: The districts of Mecklenburg-Vorpommern state were reorganized. 2016-11-01: Osterode am Harz rural district plans to merge with Göttingen.

1815: According to Wikipedia , the Kingdom of Prussia was the first to divide its provinces into Regierungsbezirke. Twenty-five of them were created in 1815-1816. Other states had similar divisions with different designations. 1945: Hesse state created and subdivided into Darmstadt, Kassel, and Wiesbaden districts.

1947: Minden district merged with the former state of Lippe to form Detmold district. 1968: Montabaur district merged with Koblenz. 1972: Aachen district merged with Köln. 1973-01-01: Territory was transferred between Nordbaden and Nordwürttemberg districts, and they were renamed Karlsruhe and Stuttgart, respectively. Territory was transferred between Südbaden and Südwürttemberg-Hohenzollern districts, and they were renamed Freiburg and Tübingen, respectively. 1978: Weser-Ems district formed by merging Aurich, Oldenburg, and Osnabrück.