Hikami County, in the western end of Tanba Province, was located in the upper reaches of the Kako-gawa River (whose upper reach portion was called the Saji-gawa River as well) that flew to the Sea of Harima in Seto Inland Sea through Harima Province.
丹波国の西端にあたる氷上郡は、播磨国を経て瀬戸内海の播磨灘にそそぐ加古川（上流部は佐治川とも呼ばれる）の上流域にあたっていた。