| Conventional Long Name: | County (Duchy) of Arenberg |
| Common Name: | Arenberg |
| Era: | Middle Ages Early modern period |
| Status: | County, Duchy |
| Empire: | Holy Roman Empire |
| Government Type: | Principality |
| Status Text: | State of the Holy Roman Empire, then State of the Confederation of the Rhine |
| Year Start: | 1549 |
| Year End: | 1810 |
| Event Pre: | County established |
| Event Start: | Gained German: [[Reichsfrei]]heit |
| Event1: | Raised to Princely county |
| Date Event1: | 1576 |
| Event2: | Joined Council of Princes |
| Date Event2: | 1580 |
| Event3: | Raised to Duchy |
| Date Event3: | 1645 |
| Event4: | Joined Confederation of the Rhine |
| Date Event4: | 1806 |
| Event End: | Mediatized to French Empire and Berg |
| Event Post: | Territories assigned to Hanover and Prussia |
| Date Post: | 1815 |
| P1: | Prince-Bishopric of Münster |
| Flag P1: | Flag of the Prince-Bishopric of Münster.svg |
| S1: | Kingdom of Hanover |
| Flag S1: | Flag of Hanover (1692).svg |
| S2: | Kingdom of Prussia |
| Flag S2: | Flag of the Kingdom of Prussia (1803-1892).svg |
| S3: | First French Empire |
| Flag S3: | Flag of France.svg |
| S4: | Grand Duchy of Berg |
| Flag S4: | Flag of the Grand Duchy of Berg (1806-1808).svg |
| Image Map Caption: | The Duchy of Arenberg in 1807 after the Napoleonic relocation |
| Capital: | Aremberg |
| Common Languages: | Moselle Franconian |
Arenberg, also spelled as Aremberg or Ahremberg, is a former county, principality and finally duchy that was located in what is now Germany. The Dukes of Arenberg remain a prominent Belgian noble family.
First mentioned in the 12th century, it was named after the village of Aremberg in the Ahr Hills, located in today's Rhineland-Palatinate region of Germany.
Aremberg was originally a county. It became an immediate (German: reichsunmittelbar) state of the Holy Roman Empire in 1549, was raised to a princely county in 1576, then became a duchy in 1645.
The territorial possessions of the Dukes of Arenberg varied through the ages. Around 1789, the duchy was located in the Eifel region on the west side of the Rhine and contained, amongst others, Aremberg, Schleiden and Kerpen.
However, although the duchy itself was in Germany, from the 15th century onward, the principal lands of the Dukes of Arenberg have been in what is now Belgium.
The pre-Napoleonic duchy had an area of 413km2 and a population of 14,800. It belonged to the Electoral Rhenish Circle and was bordered by the Duchy of Jülich, the Electorate of Cologne, the Electorate of Trier, and the County of Blankenheim.
After the French occupation of the west bank of the Rhine around 1798 (see Treaty of Campo Formio and Treaty of Lunéville), the Duke of Arenberg received in 1803 new lands: the county of Vest Recklinghausen, the county of Meppen, and later the lordship of Dülmen.
Arenberg joined Napoleon's Confederation of the Rhine, although that did not prevent it from being mediatised in 1810, with France annexing Dülmen and Meppen, and the Grand Duchy of Berg annexing Recklinghausen.
After Napoleon's defeat in 1814 and the dissolution of the Confederation of the Rhine, the former Arenberg territories were divided between the Kingdom of Prussia and the Kingdom of Hanover. In both Prussia and Hanover, the dukes became local peers subordinate to the king.
In 1826, the Arenberg territory in Hanover was named the duchy of Arenberg-Meppen, and it had an area of 2195km2 and a population of 56,700. The county of Recklinghausen, in Prussia, had an area of 780km2 and a population of 64,700.
The Dukes of Arenberg remain a prominent Belgian aristocratic family. The immediate family members of the dukes are called by the nominal title of Prince of Arenberg. The ducal family descends agnatically from the House of Ligne.
The Forest of Arenberg is located in northeastern France, and it is famous for its cobbled roads used in the classic road cycle race Paris–Roubaix. Its areas saw extensive mining in the past.
See main article: House of Arenberg.
Partition into Arenberg and Rochefort
Mediatised in 1810
