In 1816, Wiesweiler passed to the Principality of Lichtenberg, a newly created exclave of the Duchy of Saxe-Coburg-Saalfeld, which as of 1826 became the Duchy of Saxe-Coburg and Gotha. As part of this state, it passed in 1834 to the Kingdom of Prussia, which made this area into the Sankt Wendel district. Later, after the First World War, the Treaty of Versailles stipulated, among other things, that 26 of the Sankt Wendel district's 94 municipalities had to be ceded to the British- and French-occupied Saarland. The remaining 68 municipalities then bore the designation “Restkreis St. Wendel-Baumholder”, with the first syllable of "Restkreis" having the same meaning as in English, in the sense of “left over”. Wiesweiler belonged to this district until 1937, when it was transferred to the Birkenfeld district. In 1969, it was transferred, this time to the Kusel district, in which it remains today.