[2] The river rises on Mount Tangkuban Perahu and discharges into the Bay of Ciasem, Java Sea, traversing Ciasem, Subang Regency, around 90 km east of the capital Jakarta.

[4] There are a total of 21 rivers and 61 tributaries in the watershed area of (Daerah Aliran Sungai/DAS) Ciasem of 745 km2.

Compared to the other two main rivers - Ci Punegara and Ci Lamaya - Asem River and its many tributaries all flow only within the Subang Regency.

The river has a total length of 60 kilometer until the northern coast.

The warmest month is September when the average temperature is around 28 °C, and the coldest is July, at 24 °C.