 In 1974–75, with the administrative boundary reform, the district lost several councils to the neighbouring cities Düsseldorf, Duisburg, Essen, and Wuppertal.The district name also changed from Düsseldorf-Mettmann to Mettmann during this reform.However, the regional Board of Inland Revenue—the "Finanzamt Düsseldorf-Mettmann"—serves both the municipalities forming the district of Mettmann, as well as the city of Düsseldorf proper.