The Saint Mark’s organ originally was built in 1987 by Casavant Frères of Saint-Hyacinthe, Quebec, as their opus 3616 (see below for more information about Casavant). The organ was enlarged in 2016, also by Casavant. The original 1987 instrument was designed by Jean-Louis Coignet, then the firm’s Artistic and Tonal Director, in collaboration with Gary L. Garber, then the Organist-Choirmaster at Saint Mark’s. The original instrument comprised 21 stops, 27 ranks, and 1601 pipes on two manuals and pedal (see the original specifications of the 1987 organ).
Original plans called for a fuller instrument, and in 2015 Saint Mark’s contracted with Casavant to enlarge and complete the parish organ. The completion plan, adapted by current Casavant Tonal Director Jacquelin Rochette in collaboration with Dr. Tyler W. Robertson, then the Organist at Saint Mark’s, included the creation of a new expressive division and a new, movable console with three manual keyboards. Completed in July 2016, the instrument now comprises 35 stops, 41 ranks, and 2450 pipes (see the current specifications of the completed organ).