Study carried out in the Baliajong River has revealed a hidden trove of rich geological heritage. The river is located about 3 km northeast of Tandek Town in the Kota Marudu District, Northern Sabah. The prominent geological heritage of the area is an ancient oceanic crust of Lower Cretaceous to Paleocene age exposed along the Baliajong River. The ancient oceanic crust comprises predominantly of basalts and associated igneous and sedimentary rocks and forms the basement rock of northern Sabah. These rocks form part of an ophiolite, a slice of the sea floor that was uplifted to the surface during mountain building process. Besides the ancient oceanic crust, the other interesting features of this site are the various geomorphological features such as a periodic subterranean stream that forms a cave, waterfalls, U and V-shaped river valleys and the active geomorphological processes that still shape the area. The Baliajong River is also rich in mining history where manganese was mined in the early 20 th century. Remains of railway that was used to transport the manganese ores could still be found. The area is also rich in biodiversity and the riparian forest is still intact. The Baliajong River which is rich in geodiversity, biodiversity and history could be promoted as a geotourism destination. The spin-offs from the geotourism development could benefit the locals and that would encourage them to conserve the geoheritage resources in the area.