Mayor The current Lord Mayor (
Oberbürgermeister) of Hamm is Marc Herter of the
Social Democratic Party (SPD) since 2020. The Mayor is directly elected for a five-year term. Prior to the 1999 local administration reform in North Rhine-Westphalia, the
Oberstadtdirektor was the chief executive of the city, and was chosen by the city council. The most recent mayoral election was held on 14 September 2025, and the results were as follows:
City council The Hamm city council governs the city alongside the Mayor. The most recent city council election was held on 13 September 2020, and the results were as follows:
Incorporations In 1939, 1968 and 1975 Hamm incorporated several towns and municipalities: in 1939 the village Mark (which the Counts and the county took the name of) and in 1968 the villages of Berge and Westtünnen. In the reorganisation of 1975, the following towns and municipalities were incorporated into the City of Hamm: • The town of
Bockum-Hövel, Lüdinghausen district • The town of
Heessen, Beckum district • The municipality of
Uentrop, Unna district, formed in 1968, including the municipalities of Braam-Ostwennemar, Frielinghausen, Haaren, Norddinker, Schmehausen, Uentrop, Vöckinghausen and Werries • The municipality of
Rhynern, (Unna district, without Hilbeck incorporated by Werl), formed in 1968, including the municipalities of Allen, Freiske, Hilbeck, Osterflierich, Osttünnen, Rhynern, Süddinker and Wambeln • The municipality of
Pelkum, (Unna district), formed in 1968, including the municipalities of Herringen, Lerche, Pelkum, Sandbochum, Weetfeld and parts of Wiescherhöfen. The number of citizens more than doubles from 83.000 in 1974 to 173.000 in 1975.
City structure Hamm has seven quarters (''''), each divided into residential areas like City, which actually means the center of the city around the Pauluschurch or like Hövel-Radbod near the former entrance to the coalmine Radbod in the quarter Bockum-Hövel. The following table shows the situation in 2006. Every quarter is named with the prefix Hamm, like Hamm-Bockum-Hövel or Hamm-Mitte. The former town Bockum-Hövel today forms the quarter with the largest number of inhabitants, closely followed by the centre of the city
Hamm-Mitte. The latter is the smallest quarter by metric size. ==Twin towns – sister cities==