The highest point in the district is the Ulu Titi Basah peak in the Titiwangsa Mountains.

[citation needed] At that time, Tun Saban had moved to Upper Patani and stayed at Beredung Budi.

The area then under Thai control included what is today Gerik, Pengkalan Hulu (Kroh), Kerunai, the Belum forest and the Temenggor Lakes.

[citation needed] An adjustment in 1899 transferred Gerik town and the surrounding commune to the Federated Malay States, which Perak was part of.

[citation needed] The present-day border, part of the longer Malaysia–Thailand border, was finalised in 1909, when the districts of Pengkalan Hulu, Kerunai, Belukar Semang, Belum and the present-day Temenggor Lakes were transferred to the Federated Malay States.