In 1866, Nassau became part of the new Prussian province of Hesse-Nassau with Kassel as its capital. This was also the center of the Provincial Association of Hesse-Nassau, which was established in the fall of 1867 and was responsible for the self-administration of the new province. In 1885, this was modeled on the older Prussian provinces by provincial regulations. However, due to the different traditions of the two administrative districts, it was decided to establish two district municipal associations based in Kassel and Wiesbaden.

Since then, the "District Association of the Wiesbaden Administrative District" has been working in Wiesbaden. As in Kassel, its work was determined by a regional municipal council. From 1907, the venue was the new Landeshaus. The municipal administration was headed by the state director elected by the municipal state parliament, who was supported by a municipal committee.

In the 1920s, the administration was responsible for tasks in the following areas: road construction and transport (country roads, small railroads, Lahn canalization, Rhine-Main airline), insurance and banking, cultural affairs, state welfare association (state welfare for the poor), welfare education, main welfare office for war-damaged and surviving dependants, care for the blind and deaf, tuberculosis treatment, psychiatry, curative education, orthopaedics, care for the elderly. The Wiesbaden association was responsible for around 15 welfare facilities (in particular sanatoriums and nursing homes, clinics, youth homes and special schools).

In Wiesbaden, the district municipal association included in particular the fire insurance institute, life insurance institute, state bank, state library, state office for cultural-historical land antiquities and the Alfred-Erich-Heim orthopaedic clinic.

After 1933, local self-government was also abolished at provincial level; from then on, both district associations were under the control of the Chief President in Kassel. Opponents of the regime were dismissed, including provincial councillor Dr. Friedrich Stöffler. Due to the special National Socialist commitment of the new head of the institutional department, Otto Friedrich (Fritz) Bernotat, the administrative district of Wiesbaden played a central role in the Reich-wide program of murdering sick and disabled people in sanatoriums and nursing homes from 1939-45. Around 1,000 disabled infants were killed in the "children's special wards" on the Eichberg near Eltville and in the Kalmenhof in Idstein. Hadamar was the central killing center for Nazi "euthanasia". One in two of the "desk perpetrators" in Wiesbaden was released in 1945, but no one was punished.

After 1945, the municipal association continued to exist under the leadership of a municipal committee with local politicians from various parties (chaired by state governor Otto Witte) and played a decisive role in the reconstruction of the administrative district. From 1953, the social tasks of the district association were carried out by the new Hesse State Welfare Association, while road construction, economic development and culture were transferred to the state, the municipalities and corporations under their own law.

Since 2013, a memorial plaque on the Landeshaus, now the Hessian Ministry of Economics, has commemorated the building's function during the Nazi era.