The first person to permanently settle in the area was Jean-Baptiste Lafond, in 1835.

First incorporated as the village of Somerset, the settlement was officially incorporated as the village of Plessisville in 1855 in honour of Monseigneur Octave Plessis, bishop of Quebec at the time.

[5] Plessisville's history dates back to 1835, when its first resident, Jean-Baptiste Lafond, settled in the area.

By 1845, the population had grown to approximately 143 people, making it the oldest municipality in the Bois-Francs region.

[6] In 1885, a fire destroyed sixty homes, the foundry, the presbytery, and the church, marking a major turning point in its development.