North Rhine-Westphalia, is the most populous of the 16 states of Germany.

North Rhine-Westphalia is located in Western Germany covering an area of 34,084 square kilometres (13,160 sq mi), which makes it the fourth-largest state. Apart from the city-states it is also the most densely populated German state. NRW has a population of 17.9 million making it the largest German state by population and features 30 of the 81 German municipalities with over 100,000 inhabitants, including Cologne (over 1 million), the state capital Düsseldorf, Dortmund and Essen (all about 600,000 inhabitants) and other cities predominantly located in the Rhine-Ruhr metropolitan area, the largest urban area in Germany and the third-largest on the European continent. The location of the Rhine-Ruhr at the heart of the European Blue Banana makes it well connected to other major European cities and metropolitan areas like the Randstad, the Flemish Diamond and the Frankfurt Rhine Main Region.

North Rhine-Westphalia was established in 1946 after World War II from the Prussian provinces of Westphalia and the northern part of Rhine Province (North Rhine), and the Free State of Lippe by the British military administration in Allied-occupied Germany and became a state of the Federal Republic of Germany in 1949. The city of Bonn served as the federal capital until the reunification of Germany in 1990 and as the seat of government until 1999.

Culturally, North Rhine-Westphalia is not a uniform area; there are significant differences, especially in traditional customs, between the Rhineland region on the one hand and the regions of Westphalia and Lippe on the other. The state has always been Germany's powerhouse with the largest economy among the German states by GDP figures.

Rhineland-Palatinate is a western state of Germany. It covers 19,846 km² (7,663 sq mi) and has about 4.05 million residents. It is the ninth largest and sixth most populous of the sixteen states. Mainz is the capital and largest city. Other cities are Ludwigshafen am Rhein, Koblenz, Trier, Kaiserslautern and Worms. It is bordered by North Rhine-Westphalia, Saarland, Baden-Württemberg and Hesse and by the countries France, Luxembourg and Belgium.

Rhineland-Palatinate was established in 1946 after World War II, from parts of the former states of Prussia (part of its Rhineland province), Hesse and Bavaria (its former outlying Palatinate kreis or district), by the French military administration in Allied-occupied Germany. Rhineland-Palatinate became part of the Federal Republic of Germany in 1949 and shared the country's only border with the Saar Protectorate until the latter was returned to German control in 1957. Rhineland-Palatinate's natural and cultural heritage includes the extensive Palatinate winegrowing region, picturesque landscapes, and many castles and palaces.

Saarland is a state of Germany in the west of the country. With an area of 2,570 km² (990 sq mi) and population of 995,600 in 2015, it is the smallest German state in both area and population apart from the city-states of Berlin, Bremen, and Hamburg.[3] Saarbrücken is the state capital and largest city; other cities include Neunkirchen and Saarlouis. Saarland is mainly surrounded by the department of Moselle (Grand Est) in France to the west and south and the neighboring state of Rhineland-Palatinate in Germany to the north and east; it also shares a small border about 8 kilometres (5 miles) long with the canton of Remich in Luxembourg to the northwest. Saarland was established in 1920 after World War I as the Territory of the Saar Basin, occupied and governed by France under a League of Nations mandate. The heavily industrialized region was economically valuable, due to the wealth of its coal deposits and location on the border between France and Germany. Saarland was returned to Nazi Germany in the 1935 Saar status referendum. Following World War II, the French military administration in Allied-occupied Germany organized the territory as the Saar Protectorate on 16 February 1946. After the 1955 Saar Statute referendum, it joined the Federal Republic of Germany as a state on 1 January 1957. Saarland used its own currency, the Saar franc, and postage stamps issued specially for the territory until 1959.