Postal codes have existed in Germany for around 150 years, but they were only standardized nationwide in 1961. Since July 1, 1993, postal codes have been 5 digits long. Between 1941 and 1961, they were 2 digits long, and between 1961 and 1993, they were 4 digits long.
Each digit consists of a number between "0" and "9". The first digit of the five-digit postal code designates the zone, the second digit the region. For this reason, the first two digits are often referred to as the postal code region or leading region, starting in the south. The following digits range from 20 to 200 and indicate the respective municipalities. These are then divided up, partly according to population and partly alphabetically.
The city of Cologne is divided into 86 districts, also known as "Veedel," which are grouped into nine boroughs. There are 45 different postal codes in Cologne. Few cities have more postal codes—Berlin, for example. In the districts on the left bank of the Rhine, the postal code begins with "50." These include, for example, the districts "Innenstadt," "Rodenkirchen," "Lindenthal," "Ehrenfeld," "Nippes," and "Chorweiler." On the right bank of the Rhine, the postal code begins with "51." These include, for example, "Porz," "Mülheim," and "Kalk." 50667 is the lowest postcode in Cologne and covers the Altstadt-Nord district. The highest postcode in Porz is "51149."
