Plympton–Wyoming is a town in the Canadian province of Ontario, located in Lambton County immediately east of Sarnia. It is the seat of the La…Plympton–Wyoming is a town in the Canadian province of Ontario, located in Lambton County immediately east of Sarnia. It is the seat of the Lambton County Council. The name Wyoming derives from the Munsee name xwé:wamənk, meaning "at the big river flat." Plympton is named after Plympton in Devon, England.