Province of Hesse-Nassau

The Province of Hesse-Nassau (German: Provinz Hessen-Nassau) was a province of the Kingdom of Prussia from 1868 to 1918, then a province of the Free State of Prussia until 1944.

The Prussian province was officially formed in 1868 by a Royal Decree of 7 December 1868, which merged the two administrative districts of Kassel and Wiesbaden; however, it had already come into being through the annexations of Hesse-Kassel, Nassau, and Frankfurt in 1866 and was organized by decrees of March 1867 (concerning the municipal constitutions).