The headwaters of the Isfana are several unnamed glaciers at roughly 2,500 metres (8,200 ft) elevation in the northern region of the Turkestan Range called Altynbeshik (Kyrgyz: Алтынбешик; Uzbek: Oltinbeshik).

[7] The portion of the river that runs west from the Dagana Gorge to eastern Razzakov is called Tegirmenlik (variously spelled as Тегирмелик[6] and Тегермалик[1] in Kyrgyz; Uzbek: Tegirmonlik),[4] and the portion that flows through Razzakov is called the Say (Kyrgyz: Сай; Uzbek: Soy), which literally means a "creek".

[1] The Taylan Creek is also fed by several unnamed glaciers at roughly 1,800 metres (5,900 ft) elevation in Kekche-Tau Mountain (Kyrgyz: Кекче-Тау; Uzbek: Quchchi) in the Turkestan Range.

[1] The portion of the Taylan Creek that runs from the eponymous village through Razzakov until it merges with the Say is called the Uzunsay (Kyrgyz: Узунсай; Uzbek: Uzunsoy).

After travelling north from Razzakov for roughly 40 kilometres (25 mi), the Isfana River enters Jabbor Rasulov District of Tajikistan.