Montabaur was divided into the counties of Oberwesterwaldkreis (Westerburg), Loreleykreis (Sankt Goarshausen), Unterlahnkreis (Diez) and Unterwesterwaldkreis (Montabaur)...

1961, the St. Goarshausen district was renamed Loreleykreis; in 1969, the Unterlahnkreis and Loreleykreis districts were merged into the new Rhein-Lahn-Kreis...