It was declared a National Monument under old NMC legislation on 27 January 1938.

 
This English fort or earthworks is situated just east of the national road at Marabastad, a few kilometres south of Polokwane, on the farm Sand River. The British manned seven forts in the Transvaal during the First Transvaal War of Independence (1880–1881); they were situated at Pretoria, Potchefstroom, Rustenburg, Lydenburg, Wakkerstroom, Standerton and this one at Marabastad.
This fort was established after the Battle of Bron and is a Provincial Heritage Site!
Geolocation
-25° 44' 27.6", 28° 10' 1.2"
Further Reading

https://www.sahistory.org.za/article/first-anglo-boer-war