[6][7] When John Galt founded Guelph on April 23, 1827, he allocated the highest point in the centre of the newly founded town to Roman Catholics as a compliment to his friend, Bishop Alexander Macdonell, who had given him advice in the formation of the Canada Company.

Built of local limestone in High Victorian Gothic Revival style, the Church of Our Lady is considered to be Connolly's masterpiece.

[3] Matthew Bell, a well-known Guelph artisan, was responsible for some of the carvings on the exterior as well as on the interior pillars of the church.

A slide show available on the Basilica's web site provides high resolution imagery of the final results.

[11] The project had been directed by Monsignor Dennis Noon who planned to retire in June 2019 after 16 years at this parish.

[12] On 8 December 2019, Pope Francis issued an official decree granting the solemn crowning of the venerated Marian image in the basilica.

[13] The Government of Canada's Federal Designation document provides additional specifics as to the character defining elements:[14] French Gothic Revival, including a cruciform plan with side aisles, prominent nave, triforium arcades, apse with radiating chapels and ambulatory, twin-towered façade, spire at the central groin vault, and large rose windows; the sense of verticality, created by the use of steeply pitched roofs with gables, dormers, pinnacles, pointed arches, and tall narrow window openings; the symmetrically organized façade with its twin square towers with pinnacles and paired openings, massive rose window with bar tracery set in a moulded pointed arch, row of lintel statuary set within a blind arcade, and carved tympanum; the division of side elevations into bays defined by engaged buttresses, with each bay accented by a pointed arch and a stained glass window; the north and south transepts, each distinguished by two lancet windows below a large, stained-glass, rose window with flanking narrow pinnacles; the polygonal apse, consisting of radiating gabled chapels with another level of gables above; the extensive use of pointed arches and stained glass windows with bar tracery throughout the composition; the Gothic Revival styling of the interior, including, tall pointed-arch windows in the chancel, clerestories inset with rose windows, stained-glass windows, nave-arcades with false triforium-galleries, granite columns with acanthus capitals supporting the aisle arcades, and rib vaulting; the high quality design and craftsmanship of its interior, including its wood and stone carving, its stained glass, its stencilling, its ironwork, its mosaics, and its excellent acoustics; its prominent siting at the top of a hill overlooking the city; viewscapes to and from the church and the city.The City of Guelph's zoning by-laws establish "protected view areas" that are designed to ensure clear sight lines to the Church of Our Lady from various vantage points in the downtown core.

[15] Nonetheless, the new Wilson Street parkade at the Market, constructed by the city and opened in late 2019, obstructs views of the church from some locations in the downtown area.