Regierungsbezirk Montabaur followed by Koblenz Government Region
History
Regierungsbezirk Wiesbaden, formed in 1866 as part of the  Prussian province of Hesse-Nassau, had been divided by after the Second World War by the occupying powers as it lay astride a zone boundary. The majority of the Regierungsbezirk lay in the American Zone and became part of the state of Hesse in 1945. The Regierungsbezirk of Montabaur had to be created for the smaller northwestern part and became part of the state of Rhineland-Palatinate in 1946.
The Regierungsbezirk of Montabaur was dissolved on 1 October 1968 and incorporated into  Koblenz. The area of Regierungsbezirk Montabaur largely corresponds to the modern counties of  Rhein-Lahn-Kreis and Westerwaldkreis.