Arenberg, also spelled as Aremberg or Ahremberg, is a former county, principality and finally duchy that was located in what is now Germany.

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.

It became an immediate (reichsunmittelbar) state of the Holy Roman Empire in 1549, was raised to a princely county in 1576, then became a duchy in 1645.

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.

In 1826, the Arenberg territory in Hanover was named the duchy of Arenberg-Meppen, and it had an area of 2,195 km2 (847 sq mi) and a population of 56,700.