Postmasburg is a town in the Northern Cape province of South Africa. The Town is located approximately 170 km east of Upington. It is 67 km n…Postmasburg is a town in the Northern Cape province of South Africa. The Town is located approximately 170 km east of Upington. It is 67 km north of Griquatown and 58 km west-south-west of Daniëlskuil.