the ministry of magic

The Ministry of Magic (M.o.M.) is the main governing body of the magical community of Great Britain (i.e. England, Scotland and Wales) and Ireland, with the intention of preservation of magical law. The Ministry connects the British government to the wizarding world. It is located underground, beneath Diagon Alley.

Aside from the office of the Minister of Magic and the courtroom of the Wizengamot, departments include Magical Law Enforcement, Magical Accidents and Catastrophes, Regulation and Control of Magical Creatures, International Magical Cooperation, Magical Transportation, Magical Games and Sports, and the Department of Mysteries. see here for the offices within each dept.