Brief History of the Iban Migration into Sarawak
a. The North-West: Lupar River, Bukit Balau
From here, Iban proceeded westward into the Sebuyau, Sadong and Samarahan river basins.
b. The North-East : Saribas-Skrang River (Sandin 1967)
This group came into contact with the pre-existing population of the Baketan and the Seru. The Baketan, after some initial resistance, accommodated themselves to the way of the newcomers, while the Seru strongly opposed Iban incursions. A number of the Seru were converted to Islam and thereby became ‘Malay’.
c. The East : Ulu Ai, Engkari, Lemanak
From here, Iban proceeded eastward into the Baleh river basin (Masing 1997).