Zastron lies at the foot of the Aasvoelberg which is the highest peak in the Free State province (2207m, or approx. 7240 imperial feet). Close to the border of that mountainous country Lesotho, this territory is stark and beautiful.

The town is named after Ms Johanna Sibella Zastron (a corruption of the German name Zatrow), who married J.H. Brand, President of the Orange Free State Republic from 1864 to 1888. Zastron was laid out in 1876 on Jan Hendrik de Winnaar's farm Verliesfontein and became a municipality in 1881. The inhabitants of nearby Rouxville had so vigorously opposed the founding of Zastron that the Free State Volksraad (Boer parliament) waited six years to recognize the town.

The original farm owner led a precarious existence in this zone flanked by the Caledon and Orange Rivers. In the mid 19th century when the Basotho, Voortrekkers and San were continually contesting this terrain, this was dangerous countryside, and cattle-rustling abounded. The presence of the San in this area predates the arrival of the Basotho and the Voortrekkers. Excellent examples of San rock art (both paintings and engravings) still exist in their ancient caves in the hills.

A road map showing Zastron's location in the province of the Free State and its positon relative to Lesotho is at http://www.routes.co.za/fs/zastron/.