The Hanuman River (Thai: แควหนุมาน, rtgs: Khwae Hanuman, IPA: [kʰwɛː hànúmaːn]) originates in South San Kamphaeng Mountain Range, the Khao Yai National park. It begins at the confluence of many small tributaries at Tambon Samphan Ta, Na Di District, Prachin Buri Province. It flows southward and joins the Phra Prong River to become the Prachin Buri River in Kabin Buri district, Prachinburi Province. The river is 25 kilometres (16 mi) long.