Perth County was mainly settled through the agency of the Canada Company which opened a road from the site of Stratford to Goderich. It was officially established around 1850 out of the former Huron and Wellington Districts and had 11 original townships.

Blanshard Township was named after Richard Blanshard, Director of the Canada Company, and opened in 1830. Hibbert Township also opened in that year and named in honour of William T. Hibbert, Director of the Canada Company. First pioneer was Thomas Fox who received 200 acres (0.8 km2) of land from the Company on the condition he open an inn for travelers on the Huron Road.

In 1831 William Sergeant was given a lot by the Canada Company on the condition that he open an inn. In 1832 he raised the first frame building in the region by the Avon River and called it the "Shakespeare Hotel." First purchaser of land was John Sharman (1834), a blacksmith from Bedfordshire, England. His son, Henry, was the first child born within the limits of the city.

In 1998, the county was rearranged by reducing fourteen municipalities to four. Only the City of Stratford and the Town of St. Marys were unaffected.