Khatlon Province in the context of "Romanization of Tajik"

Khuttal, frequently also in the plural form Khuttalan (and variants such as Khutlan, Khatlan, in Chinese sources K'o-tut-lo) was a medieval region and principality on the north bank of the river Oxus (modern Amu Darya), lying between its tributaries Vakhsh and Panj. It corresponds roughly to the modern Khatlon Province of Tajikistan.

The pre-Islamic Principality of Khuttal played an active role, sometimes as an ally, sometimes as an enemy, of the Umayyads during the Muslim conquest of Transoxiana, and it was not until 750/1 that the Abbasids finally established direct control over it. A branch of the Banijurids of Tokharistan ruled over the area under the Abbasids, and acknowledged the suzerainty of the Samanids in the 10th century. The area apparently retained an autonomous line of rulers in the 11th–12th centuries, when it came first under the loose control of the Ghaznavids, and after the middle of the 11th century of the Seljuq Empire. With the decline of Seljuq power, Khuttal passed to the control of the Ghurids and the Khwarazmshahs, under whom no native princely line is known. In the 13th century Khuttal became a part of the Mongol Empire and of its successor, the Chagatai Khanate, emerging once again as an autonomous principality following the latter's disintegration in the mid-14th century. In the 16th century, the Shaybanids took over Khuttal, and the name itself ceases to be used, being replaced by Kulob.

Hisar (also Gissar, Gisar, Hissar, or Hisor) Valley in Tajikistan runs east–west along the southern slopes of Hisar Range and on the northern border of Khatlon Province. It is about 100 km long and up to 20 km wide in the middle, stretching from Vahdat district in the east to Tursunzoda district on the border with Uzbekistan in the west, with the capital Dushanbe and Hisar district at its center. The elevations in the valley range from 700 meters (2,300 ft) to 1,000 meters (3,300 ft). The valley is irrigated by Kofarnihon River in its upper and middle course. Warm temperatures (29 °C in the summer, 0 °C to – 1 °C in the winter) and abundant water for irrigation make the Hisar Valley one of the prime cotton growing areas in Tajikistan.

The Qizilsu (Tajik: Қизилсу) or Kyzylsu (Russian: Кызылсу) is a river that rises on the southern slopes of the Vakhsh Range in the north-east of Tajikistan's Khatlon Region and runs south-west until joining the Panj on the border with Afghanistan. The river is 230 kilometres (140 mi) long and has a basin area of 8,630 square kilometres (3,330 sq mi). It merges with the Yakhsu (Akhshu) as a major left tributary south of the town of Kulob. It irrigates the cotton-growing Qizilsu Valley between Kulob and Panj in the south-east of Khatlon Province. It is not the Kyzyl-Suu River that rises in Kyrgyzstan and flows through Tajikistan as Surkhob, then Vakhsh, following a course north-west of Qizilsu.