Mugan plain in the context of Sabirabad (city)

Caspiane or Kaspiane (Greek: Κασπιανή, Armenian: Կասպք Kaspkʿ) was the land populated by the tribe of Caspians, after whom it received its name. Originally a province of the Medes in the 3rd-2nd centuries BC, the land of the Caspians was conquered in the 2nd century BC, then passed to Caucasian Albania under Sassanid Persian suzerainty in the 5th century, and later became an independent state. In the 2nd century AD, it became known as Paytakaran, and after 387 AD became a part of the Caucasian Albanian larger region of Balasakan.It roughly corresponded to the modern Mugan plain and Qaradagh regions.

Arran (Middle Persian form; Persian: اران or اردهان), also known as Aran or Ardhan, was a geographical name used in ancient and medieval times to signify a historically-Iranian region which lay within the triangle of land, lowland in the east and mountainous in the west, formed by the junction of the Kura and Aras rivers, including the highland and lowland Karabakh, Mil plain and parts of the Mughan plain. In pre-Islamic times, it corresponded roughly to the territory of the modern-day Republic of Azerbaijan. The term is the Middle Persian equivalent to the Greco-Roman Albania. It was known as Aghvania, Alvan-k in Armenian, and Al-ran (Arabized form of Arran) in Arabic.

Today, the term Aran is mainly used in Azerbaijan to indicate territories consisting of Mil and Mughan plains (mostly, Beylagan, Imishli, Kurdamir, Saatly, Sabirabad provinces of the Republic of Azerbaijan). It has also been used by Iranian historian Enayatollah Reza to refer to the country of Azerbaijan, freeing the name "Azerbaijan" to refer to a region within Iran. The bulk of the territory of the republic of Azerbaijan was the historic Shirvan, as well as Quba/Qubbah).