South Africa
On 16 December 1838 the Battle of Blood River took placenear the Ncome River in KwaZulu Natal. The Battle of Blood River was between the Voortrekkers under the leadership of Andries Pretorius and the Zulu's under the leadership of Dingane the Zulu King. About 10 000-20 000 Zulu warriors led by Dingane's generals Dambuza (Nzobo) and Ndlela kaSompisi attacked the Voortrekkers, but the 470 Voortrekkers, with the advantage of gun powder, warded them off. The battle began at dawn and was over by midday. More than 3000 Zulu casualties were counted around the laager. Only, 3 Voortrekkers (including Voortrekker leader Pretorius) were wounded, none were killed. The Ncome River became red with the blood of the slain. Hence the river became known as "Blood River".
https://www.sahistory.org.za/dated-event/battle-blood-river