At 305 feet (92.9 m), the cathedral's spire makes it the second tallest church in Canada, after Saint Joseph's Oratory in Montreal. It was designed by Fredrick Cumberland and is a prime example of Gothic Revival architecture. It opened for services on June 19, 1853, and the clocktower was finished in 1874, with the clock being installed a year later. The total length of the cathedral is 198 feet, with a maximum width of 98 feet.
The cathedral's tower clock has five bells that still ring through the city today, and the chiming clock is "one of the finest examples of a chiming public clock anywhere in the world." The tower also houses a full peal of 12 change-ringing bells, the largest such peal in North America.