Rhineland-Palatinate
On 10 July 1945 the occupation authority on the soil of the present-day Rhineland-Palatinate transferred from the Americans to the French. To begin with, the French divided the region provisionally into two "upper presidiums" ("Oberpräsidien"), Rhineland-Hesse-Nassau (for the hitherto Prussian government districts and regions of Koblenz, Trier, and Montabaur) and Hesse-Palatinate (for the hitherto Bavarian Palatinate and old Hessian-Darmstadt province of Rhenish Hesse). The formation of the state was ordained on 30 August 1946, the last state in the Western Zone of Occupation to be established, by Regulation No. 57 of the French military government under General Marie-Pierre Kœnig. It was initially called Rhenish-Palatinate ("Rheinpfälzisches Land" or "Land Rheinpfalz"); the name Rhineland-Palatinate ("Rheinland-Pfalz") was first confirmed in the constitution of 18 May 1947.
Palatinate (region)
The union with Bavaria was finally dissolved following the reorganisation of German states during the Allied occupation of Germany after World War II. While Bavaria itself was part of the U.S. occupation zone, the Palatinate was occupied by French forces. The French reorganised their occupation zone by founding new states, so that in 1947 the Palatinate was combined with Rhenish Hesse ("Rheinhessen"), the former parts of the People's State of Hesse left of the Rhine, and the southern part of the Prussian Rhine Province, to form the German federal state of Rhineland-Palatinate. The Palatinate formed the administrative district ("Regierungsbezirk") Pfalz. 
This reorganisation came with smaller losses of former district territory to the Saarland, especially in the area of Sankt Wendel. As part of the 1969 administrative reform, some minor border changes were made in the north. The Diocese of Speyer and the Evangelical Church of the Palatinate still exist today largely based on the historic boundaries of the old Bavarian district of "die Pfalz".