St. Patrick's Co-Cathedral is a Catholic cathedral in Billings, Montana, United States.

[2] By the turn of the 20th century Billings was in need of a larger church and St. Patrick's was established.

The altar, communion rail, Stations of the Cross and pews were all replaced with new furnishings.

Further modifications were made to the interior of the church in the 1960s and 1970s in response to the liturgical reforms of the Second Vatican Council.

[3] At that time St. Patrick's Church joined St. Ann's Cathedral in Great Falls as the co-cathedral of the diocese.