The longest river in South Africa, which rises in the Drakensberg Mountains in north-eastern Lesotho and flows generally westward for 1,859 km (1,155 miles) to the Atlantic, forming the border between Namibia and South Africa in its lower course.
Definition of Orange River in US English:
Orange River
proper noun
The longest river in South Africa, which rises in the Drakensberg Mountains in northeastern Lesotho and flows westward for 1,155 miles (1,859 km) to the Atlantic Ocean. It forms the border between Namibia and South Africa.