It is approximately 78 km long, forming at the confluence of two small rivers, the Qugwala in the West and the Mtyolo in the East.

Its catchment area of 441 km2 makes it one of the smallest river basins on South Africa's eastern coast.

[1] It was near the mouth of this river in 1938 that Captain Hendrik Goosen trawled a catch of fish, one of which Marjorie Courtenay-Latimer preserved.

This fish was later identified as a coelacanth species, which was previously thought to be long extinct and was at that point in time only known from the fossil record.

[2] Historically the Chalumna River formed the northern border of the former Ciskei shoreline until 27 April 1994 when all the Apartheid era political regions were reincorporated into South Africa.