Weilburg is, with just under 13,000 inhabitants, the third biggest town in Limburg-Weilburg district in Hesse, Germany, after Limburg an der Lahn and Bad Camberg.

Besides the main town, in which just under 40% of the inhabitants live, the outlying centres of Ahausen, Bermbach, Drommershausen, Gaudernbach, Hasselbach, Hirschhausen, Kirschhofen, Kubach, Odersbach and Waldhausen also belong to Weilburg's municipal area.

It is believed that the earliest traces of settlers in the area around Weilburg are attested by finds from La Tène times from the Scheuernberger Kopf (mountain) near Kirschhofen.

Six years later King Conrad I, whose father had been buried in the fortification after having fallen in battle while fighting the Babenbergers near Fritzlar in 906, founded a church and an abbey.

In 918, the Wilineburg (castle) gained special historic importance when King Conrad I, lying on his deathbed, recommended to his brother Eberhard that he deliver the Imperial insignia to his bitterest rival, the Saxon duke Heinrich (Weilburger Testament).

Weilburg thus became one of the most fully preserved examples of a small German residence town from the time of absolutism.

In 1866, the Duchy of Nassau was annexed by Prussia, and in 1871 it became part of the newly established German Empire.

The last non-Nazi mayor chosen by the town council, Diffenhardt, was ousted in a no-confidence vote instigated by the Nazis in the summer of 1933.

During World War II, in 1939–1941, it was the location of the Oflag IX-B prisoner-of-war camp for Polish and Belgian officers and orderlies.

The middle façade of the palace's orangery collapsed after an aerial bomb meant for the Weilburg railway station fell right in front of the gate and exploded.

The cluster village lies right on the Lahn where the Grundbach empties into it, which explains why the three mills that once stood here.

There is historical evidence of an oil mill in 1666, and also, a blast furnace for smelting ironstone mined in the area is mentioned in 1679.

At the time of its first mention, the community belonged to the Trier Burgmann Johann von Schupbach, who resided in Montabaur.

Waldhausen was first mentioned in documents in 881 in the Prüm Abbey's Golden Book, in which it is known as Mark Ualthusa in a passage dealing with the settlement there and the Carolingian forest holdings.

The municipal election held on March 6, 2016, yielded the following results: Johannes Hanisch has been mayor since July 1, 2017.

The gate, which is shut and strewn with black, is overlaid with a blue inescutcheon, which itself bears the Nassau lion in gold.

The colours are drawn from the tinctures in the coat of arms, with yellow standing for the gold, and white for the silver.

Housed in the former chancellery building is Weilburg's Bergbau- und Stadtmuseum ("Mining and Town Museum"), which has at its disposal an exhibit area of 1 200 m2.

Since May 2008, one part of the museum has also housed roughly one hundred works of Chinese cut paper artworks.

In the outlying centre of Gaudernbach is found the Deutsche Baumaschinen-Modellmuseum ("German Building Machine Model Museum").

At the Freienfels castle ruins, five kilometres from Weilburg, the Freienfelser Ritterspiele (knightly games) are held yearly about 1 May.

After the Baroque expansion under Johann-Ernst of Nassau-Weilburg, it takes in almost half of the Old Town, and including the Protestant Schlosskirche from the early 18th century.

For the Gymnasium Philippinum Weilburg, a representative building was built in the 18th century, which now houses the district and town library.

It was originally the Weilburg Counts' hunting ground, but today it is a zoological garden visited by 110,000 people every year.

Great parts of this cleft cave's walls are set with countless calcite crystals and calc-sinter.

With a length of roughly 200 m, a breadth of up to 23 m and a height of up to 30 m the cave is believed to be Germany's biggest single natural underground chamber.

The town lies on the Lahntal railway (serving Koblenz, Limburg, Weilburg, Wetzlar and Gießen) and belongs to the Rhein-Main-Verkehrsverbund.

Weilburg can be reached by Bundesstraßen 49 and 456, which link it to Autobahnen A 3 (Cologne–Frankfurt) from Limburg and A 45 (Dortmund–Aschaffenburg) from Wetzlar, as well as from the Frankfurt Rhine Main Region.

Weilburg 2006 Paul von Hindenburg, Adolf Hitler, Hermann Göring, Jakob Sprenger and Prince Philipp of Hesse (Chief President of the Province of Hesse-Nassau) were all stripped of their civic honours in 1946 by order of the town council.