The Conestogo River is a river in Waterloo Region and Wellington County in Southwestern Ontario, Canada. The river was named by Mennonite settlers after the Conestoga River in Pennsylvania. In the 1800s there were several different spellings of the name of the river and of the nearby settlement of Conestogo, Ontario but the name ending in "o" became official. It is in the Lake Erie Basin and joins the Grand River as a right tributary at the community of Conestogo.