The entire St. Peter's Cathedral Complex is listed on the U.S. National Register of Historic Places.

[2] The original windows of the church contained simple red and white diamond-shaped panes.

Much of this work can be attributed to the architect Edwin Forrest Durang and later to the German designer Frank Mayer.

In addition to the use of stained glass in the clerestory and over the entrances, there are 15 grandiose windows focusing on the life of Christ and highlighting the Virgin Mary and other saints.

[1] The present organ was built in 1979 by Casavant Frères of Quebec, Canada, the firm's Opus 3414.