Agsu city-administrative center of Agsu district - is on the road leading to the northeast of Kurdamir in direction of Shamakhi, 37 km to Shamakhi on the bank of Agsu River. A lot of rivers in Azerbaijan have name "Agsu". They are called in this way due to origins in the snowy mountains. "Agsu" means "clean, pure water".The road to Agsu lays through the famous Agsu pass at the length of 14 km and maximal height of 900 m. Magnificent sight on Shirvan valley is opened from here in clear weather and the traveler is impressed with the immense spaces of the magnificent panorama of these palaces. When the pass is covered with the fog, each passenger feels that he moves through the clouds. There is grape silkworm cocoon procession enterprices in the district. Agsu is famous for its carpets "Birjo", "Gashed", "Pirsaganli".
A. A. Bakikhanov noted that Nadir Shah issued an order for resettlement of the inhabitants of Shamakhi to new laid down city on the bank of Agsu River, in 1735. At present, the name of Agsu city (which is the centre of Agsu district) is shown as New Shamakhi in some sources. It is related with resettlement of the inhabitants of Shamakhi to Agsu city. Since that time, historic Shamakhi has been called Old Shamakhi, Agsu – New Shamakhi.The name of the city existing in the 18th century was frequently shown as Agsu deriving from "Agsuchay". "Ruined city" – ruins of the Agsu city of the memory of the 18th century is located in the north of Agsu city.
Agsu city is the one of the important cities leading in social-political and military life of Azerbaijan in the end of Middle Ages. In 1734, Nadir Shah attacked Shamakhi with his troop. The inhabitants of Shamakhi resisted against the attack, notwithstanding Surkhay khan had left the city. In August 1734, Nadir Shah's troop overcame the resistance and the city was burnt. In 1735, Nadir Shah issued an order about laying out the new city on the bank of Agsuchay River. After construction of the new city, the inhabitants of Shamakhi were resettled here; residences of rulers of Shamakhi also were removed here.
Agsu city was repeatedly exposed to feudal attacks in the 18th century. Frequent deportation, destructions made the inhabitants disappointed in living in the city. Therefore, the inhabitants did not prepare to construct glamorous buildings, tombs, mosques, bathrooms, social and official buildings.In 1967, Agsu was entitled with city-type settlement status, in the same year it was entitled with city status.Agsu has been operated as administrative-territorial district since October 8, 1943.