Western Orissa, also referred as Kosal is a territory in western part of Orissa, India, extending from the Kalahandi district in the south to the Sundargarh district in the northwest. Western Orissa includes the districts of Balangir, Bargarh, Boudh, Deogarh, Jharsuguda, Kalahandi, Nuapada, Sambalpur, Sonepur, Sundargarh, and Aathamallik Sub-division of Angul Dist. During the Chauhan rule this land was also known as Hirakhand, literal meaning in English is the land of Diamonds. Their kingdom comprised all the present districts of Western Orissa except the dist of Kalahandi.

Prior to the 5th century, Dakshin Kosal was one of the several names by which this region was known. It is a vast geographical area, exhibiting a great degree of cultural uniformity in terms of demography and life-style.

This geographical area is also recognised by state government of Orissa as the area under Western Orissa development council (WODC). The Sonepur, Balangir, Nuapada, and Kalahandi districts of this region are also part of the Kalahandi Balangir Koraput or "KBK" area, noted for its high death rate from starvation and poverty. The book Cultural Profile of South Kosal depicts the rich history and culture of Kosalanchal.