Grand Duchy of Hesse follows Landgraviate of Hesse-Darmstadt
Administrative subdivisions
From the beginning the Grand Duchy faced the problem of bringing its various disparate parts together.  Even the core region, the Landgraviate of Hesse-Darmstadt, consisted of two separate parts: the "Old Hessian" region and the Upper County of Katzenelnbogen. In addition to this there were the territories received during secularisation and mediatisation in 1803, the treaty of the Confederation of the Rhine in 1806, and the former French areas received at the Vienna Congress in 1816. In the territorial expansion between 1803 and 1816, Hesse initially inherited and retained their particular administrative divisions. This meant that the provinces on the right bank of the Rhine, were divided into Ämtern, while Rhine Hesse retained the French administrative structure based on cantons (although partially using German terminology). The process of unifying and modernising divergent systems took almost the whole of the nineteenth century. A clear end point is 1 January 1900 when the extremely fragmented private law systems in Germany were replaced by the Bürgerliches Gesetzbuch, which applied to the Empire.The lowest level subdivision was the municipality (Gemeinde).