[citation needed] Khasso straddles both banks of the upper Senegal River roughly from Kayes to Bafoulabe, in a strip at most 60 km wide.

It is located at the transition point between the mountains to the south and the arid plans to the north, and between the Senegambia region and the Niger.

Initially oppressed by their hosts, the Fula revolted and in 1681 under the leadership of Yamadou Hawa they won their independence in battle at Toumbifara, near Bafoulabe.

They elected Séga Doua (r. 1681 - 1725), Yamadou's son, as the first fankamala, or king, of Khasso, and he quickly imposed his authority on the entire region as far as Gajaaga.

A family's status was indicated by the number of slaves it owned, leading to wars for the sole purpose of taking more captives.