The southeastern part of the township includes the municipalities of Saint-Jean-des-Piles, Grandes-Piles, Saint-Roch-de-Mékinac, sector Lac-à-la-Tortue (grouped since 2001 in the city of Shawinigan) and Garneau railway junction (located northeast of Grand-Mère).
[1] The northwestern part of the township has a relatively rugged terrain, while the land south-east (east of the Saint-Maurice River) is a rather flat plateau and has some marshy areas.
The inventory of 1814 of the assets of the Company Forges de Batiscan, refers to the Township of Radnor, which was proclaimed as a Canton on February 3, 1855, by the Government of Quebec.
This territorial designation continued to be used by the owners of Radnor Forges who operated a foundry from 1854 to 1911, in the industrial town of Fermont.
The name is inspired by the forests and mountainous landscape of Radnorshire, located in the centre of Wales in United Kingdom.