The Terek drains most of the northeast Caucasus east into the Caspian just as its sister, the Kuban, drains the northwest Caucasus west into the Black Sea. Its major tributaries are the following. In the west a fan of rivers flows east and northeast into the Terek. These are the east-flowing Malka, the Baksan, the Chegem and the Cherek with its two branches. These three join the Malka just before it reaches the Terek. The Liashen, Urukh, Duradur and Duradon flow northeast, the Ardon and its tributary, the Fiagdon flow north and the Gizeldon drains the north slope of Mount Kazbek and reaches the Terek near the mouth of the Ardon. Then there is the north-flowing part of the Terek with the Darial Pass. The great northwest bend of the Terek is cut off by the northeast-flowing Sunzha which catches most of the north-flowing rivers. These are the north-flowing upper Sunzha, the Assa, the Argun and Khukhulau. East of these are the Aksay and the Aktash which formerly dried up in the lowlands between the Sulak and the Terek. In the east the Sulak drains most of interior Dagestan and turns east to the Caspian before it reaches the Terek.