Ohrigstad (Afrikaans for Ohrig city), formerly Andries Orieg Stad, is a small town to the north of Lydenburg in the Limpopo province, South Africa.
A fort was established by a group of Voortrekkers under the leadership of Andries Hendrik Potgieter with the help of a Dutch merchant Gregorius Ohrig. The settlers arrived in 1845 and were soon afterwards decimated by malaria and forced to abandon the area. Settlers only returned once the disease was under control. On the 14 May 1873, the area was proclaimed as a public gold field after the discovery of gold in the Selati River.
The Voortrekker, Pieter Willem Prinsloo, who left the Cape between 20 June 1837 and the end of March 1838, registered a farm Dorenhoek in the Ohrigstad area on 16 March 1846. Voortrekker Fort/Ohrigstad Fort was constructed before 1847 to act as a refuge for local Voortrekker families due to the constant attacks of local Bantu tribes. It is situated in the Ohrigstad area of northern Mpumalanga province which was first settled by Europeans under the leadership of Andries Hendrik Potgieter. The Voortrekker Fort was built circa. 1847 by early pioneering Voortrekkers in modern day Mpumalanga Province, South Africa. The main purpose of the fortifications were to protect themselves and their families against possible attacks by the local tribes in the general Ohrigstad vicinity. The fort is in the same grounds as the Andries Hendrik Potgieter Gedenksaal. The fort was built using a combination of dry stone walling and mud brick layering with loopholes supported by slate stone lintels, making rifle-fire easier. The site is mostly in ruins today, however it has received Provincial Heritage status, and a new roof has been placed over the site in order to protect the mud construction.