The longest river of the Republic of Azerbaijan is the Kur whose river source is in Turkey and which flows through the Republic of Georgia, before it enters Azerbaijan. There it unites with the second longest river Aras whose river source is also in Turkey, and which is on the country's border with Iran. The major tributaries of the Kur river are the Qanix, Qabirri, Turyan, Agstafa, Shekir, Terter and Khachin rivers. The major tributaries of the Aras river are the Arpachay, Nakhchivan, Okhchu, Hekeri and Kondelenchay rivers. The largest rivers which are not tributaries of the Kur and Aras rivers are the Samur, Gudyal, Velvele, Vilesh and Lenkeran rivers.