The South Riding was defined to consist of the Townships of Goderich, Stanley, Hay, Stephen, and Usborne, and the Village of Clinton.

In 1882, the South Riding was redefined to consist of the townships of McKillop, Hullett, Tuckersmith, Stanley, and Hay, the town of Seaforth, and the village of Bayfield.

Huron South was expanded to include the townships of Hullet and Goderich, and the town of Clinton.

In 1924, Huron South was redefined to consist of the part of the County of Huron lying south of and excluding the town of Goderich, and north of and including the townships of Goderich, Hullett, and McKillop.

The electoral district was abolished in 1933 when it was redistributed between Huron North and Huron—Perth ridings.