Rettbach (Rot) is a river of Thuringia, a federal state in the central of which country?
Thuringia The Free State of Thuringia ( ; German: "Freistaat Thüringen" , ] ) is a federal state in central Germany.
People's State of Reuss The People's State of Reuss (German: "Volksstaat Reuß" ) was a short-lived country in what is now Thuringia. The state was formed on 4 April 1919 after the reigning princes of the two Reuss principalities abdicated and elections were held in both states. It united with six other small states to form Thuringia, a member state of the Weimar Republic, on 1 May 1920.