[1] The Basilica is one of the regular buildings featured in the Doors Open Ottawa architectural heritage day.

King McCord Arnoldi (architect) was responsible from 1874 to 1875 for the completion of the original design prepared in 1869 by Augustus Laver.

[5] A memorial plaque was unveiled on June 11, 1916 and is dedicated to St. Patrick's Basilica in appreciation for the privilege of worshipping in this church by the commanding officer (from 19 Jun 1916 to 13 Sep 1916) Lieutenant Colonel D.R.

[6] A World War I memorial painting, which depicts angels meeting a dying soldier on the battlefield and Jesus Christ on the cross, was erected by the parishioners and is dedicated to the soldiers of the St. Patrick's Basilica parish who fell during The Great War.

[11] The building is made of local stone[12] in the Gothic Revival style and features a carved and stencilled ceiling, marble altars, stained glass windows, and oak pews dating to 1954.

To the right of the altar is a beautiful replica of Murillo's Assumption of the Virgin Mary, hand painted by Québec nuns in 1929.

In 2009, the Basilica won the North American Copper in Architecture Awards (NACIA) in the Historical Restoration division.

[13][14][15] Work was done following the Canadian Federal Government publication Standards and Guidelines for the Conservation of Historic Places in Canada.

[12][21] Daily Masses before work (7:00 a.m., 8:00 a.m.), during lunch (12:15 p.m.), and after the workday (4:30 p.m.), with confessions before each service; Catholics citywide make use of the confessionals at Saint Patrick's.

The Saint Patrick's Singers are a group of volunteer soloist singers who provide their professional services on alternating weeks with the Basilica Choir, the oldest one at the St. Patrick's, who sing predominantly English unison music at the 11:00 a.m. Sunday Mass.