From church website:
In July 1919, a contract was signed with the Austin Organ Company (later Austin Organs, Inc.) of Hartford Connecticut, to build a large romantic organ. The organ took over two months to install, and it was possible that the choir loft, in which the organ resides, was erected at this time, as well. The dedicatory recital was performed by Dr. Marcus Kellerman on Sunday, October 24, 1920.

In 1996, Peebles-Herzog, Inc. was hired to rebuild the organ. Tonally the organ would be left alone, to sound just as it had for three-quarters of a century. Pipes numbering the thousands were removed, washed, vacuumed, and reinstalled, with volunteers doing much of the work. The organ has over 2,800 pipes in the Gallery organ, and nearly 1,000 pipes in the Echo organ.

As the instrument approaches its centennial, tastes have seemingly come full circle and there is again a growing appreciation for these vintage pipe organs. As so many have been lost to neglect or changes in taste, it is most fortunate that we have preserved today in the acoustical and visual splendor of St. Mary, a rare jewel of early 20th century American Romantic organ building.

Updated through on-line information from Michael Hughes.

Status Note: There 1998

Ded. Dr. Marcus Kellerman, 24 Oct 1920. Cleaned and repaired by Kilgen in 1955. Rebuilt 1996 by Peebles Herzog, with no tonal alterations. Original windchest rebuilt. Console computerized, new wood keyboards. [Previous organ sold in 1920 to a R. C. church in Sheboygan, WI.]