|Mayor||Udo Rau (CDU)|
|Area||17.51 km2 (6.76 sq mi)|
|Elevation||100 m (328 ft)|
|Population||4,654 (31 December 2011)1|
|- Density||266 /km2 (688 /sq mi)|
|Time zone||CET/CEST (UTC+1/+2)|
Nassau is a town located in the German Land (State) of Rhineland-Palatinate. It lies in the Lahn River valley between the cities of Bad Ems and Limburg an der Lahn. Nassau is the seat of the Verbandsgemeinde ("collective municipality") of Nassau. The town is on the German-Dutch holiday road, the Orange Route. As of 2002, it had a population of 5,209.
The earliest known surviving mention of Nassau occurs as the Villa Nassova estate of the Bishopric of Worms in a 915 deed. In 1348 the Emperor Charles IV granted it town-privileges rights together with nearby Dausenau and Scheuern. Count Dudo-Heinrich of Laurenburg had the Burg Nassau built about 1100 and his descendants began to call themselves the Counts of Nassau. Count Adolf of Nassau was elected King of the Romans from 1292 until his death on 2 July, 1298. The Counts of Nassau married into the line of the neighbouring Counts of Arnstein (Obernhof/Attenhausen), founders of the monastery at Arnstein. After the dissolution of the Holy Roman Empire in 1806, the town became part of the Duchy of Nassau.
Despite the ancient and eventful history of this town, it currently has only slightly over 5,000 inhabitants.
The town of Nassau served as the original namesake of the Duchy of Nassau, the royal House of Orange-Nassau, and the Prussian province of Hessen Nassau. Its name has also spawned a multitude of other places in the Americas, such as Nassau, the capital city of the Bahamas, and Nassau County, New York, in the United States. The name also occurs in the titles of ships, buildings, and even a type of bet used in golf.
Located in Nassau, south of the Lahn River, is the Nassau Castle. It is the eponymous ancestral seat of the counts of Nassau and thus the joint ancestral castle of the Grand Dukes of Luxembourg and Dutch royal house of Nassau.
The town is also home to the Steinische Hof, the seat of the Reichsfreiherren (Barons) vom und zum Stein, and birthplace of the Prussian Reformers and Minister Heinrich Friedrich Karl, Reichsfreiherr vom und zum Stein.
The Imperial Baron Heinrich Friedrich Karl vom und zum Stein, Prussian statesman and reformer, was born in Nassau on October 25, 1757. Here he wrote his famous Nassauer Memorandum of 1807. Stein descended from an ancient aristocratic dynasty, who had been residents of Nassau since the 12th century. The family estate lies in the centre of the town, called the Steinische Hof, which today is still in the possession of the descendants of the reformer, the Counts von Kanitz.