Only the upstream section of this river is named "Sông Pha", the downstream section to the confluence with Sông Cái is named "Sông Ông". https://thuvienphapluat.vn/van-ban/Tai-nguyen-Moi-truong/Thong-tu-33-2015-TT-BTNMT-Danh-muc-dia-danh-dan-cu-son-van-thuy-van-kinh-te-xa-hoi-Ninh-Thuan-287264.aspx