Designed by Saint John architect Matthew Stead (1808-1880), the cathedral was built for the large Irish Catholic population of Saint John, which by 1847 was over 30,000, accounting for half of the city's population. Foundation work began in 1853, dedication in 1855 and three decades later, in 1885, the completed Cathedral was consecrated "with great fanfare". The Diocese of Saint John itself was established on September 30, 1842, by Pope Gregory XVI.
In the cathedral are many large stained glass windows, myriad wood carvings and a large (ten ton) organ built by Casavant Frères of Ste. Hyacinthe, Québec, in 1952, Opus Number unknown. As of 2016 the cathedral is undergoing a much needed $10 million restoration inside and out, with every facet of the building receiving attention, from the roof to the doors to the stained glass to the organ, statuary and interior woodwork.
There are some relatively large numbers associated with the Cathedral of the Immaculate Conception:
• 400 men volunteered to dig the foundation;
• 221 stone cutters crafted the stone work;
• 3,000 arrived to celebrate the first Christmas Mass and dedication in 1855;
• the Cathedral’s spire, not completed until 1871, reaches 300 feet above sea level
(When we visited, the spire was nearly lost in the low hanging clouds).