When John Galt founded Guelph in 1827, he designated the highest point in the new city as the location for a Catholic church. Three churches have been built on the site: The first burned down, the second was outgrown, and the third is the Basilica of Our Lady Immaculate, a Gothic Revival style church that took more than 50 years to complete.

The church was designed by the renowned Ontario architect Joseph Connolly. While it was meant to rival St. Peter’s in Rome, the building was designed in the style of the Cologne Cathedral. Construction began in 1876, and in 1888 it was dedicated as the Church of Our Lady. The exterior of the church would not be finished until 1926, when the church’s two towers were finally completed.

Today the appearance of the church differs little from the way it looked in 1926. Local zoning laws prevent structures in certain areas of Guelph from rising higher than this impressive church, so it can be seen from many areas in the city. 

The church was dedicated as a national historic site in 1990 because of its unique, intricate design and prominent location. In 2014, a yearslong restoration project was completed, and Pope Francis designated the church as a minor basilica.