The longest river in the Peninsular Malaysia at 435km, the Pahang drains about three quarters of the land area in the state of Pahang.

The river actually begins from Kuala Tembeling at the confluence of two equally large and long rivers, the Jelai which drains from the eastern slopes of the Banjaran Titiwangsa, the main range of Peninsular Malaysia, and the Tembeling which has its headwaters in the Terengganu Highlands in the east. For the purpose of fixing its length, however, the Tembeling and the Pahang are taken to be one river. Otherwise, the Tembeling and Jelai are commonly, if erroneously, referred to as tributaries of the Pahang. Other main tributaries of the Pahang are the Semantan, Teriang, Bera and Lepar, one of which, Paya Bungor, comes close to the Maran – Kuantan road and is now a tourist destination with visitor facilities.

Four major town are located on or near the Pahang and its tributaries; Pekan, the royal town at its mouth, Temerloh midway on the river at its confluence with Semantan, Jerantut, the gateway to Taman Negara on the Tembeling, and Kuala Lipis at the mouth of the river bearing the same name on the Jelai.

The upper reaches of the Pahang, that is to say, the upper reaches of the Jelai and the Tembeling, run through ruggedly beautiful and wild country suitable for adventure travel. The headwaters of the Jelai, for example, rise in Cameron Highland and have been frequently traveled by adventurers by rafts and canoes. The Tembeling and its tributaries – the Sat, Sepia and Kenyam – run through Taman Negara and are popular angling sites.