Kapuas River
"N. borneanus" is found in central south Borneo, in the Indonesian provinces of West, South, and Central Kalimantan. Its range extends south of the Kapuas River and east to the Barito River. However, "N. borneanus" is not found in the extreme southwest of the island. It may be sympatric with "N. bancanus" in the province of West Kalimantan.