My guess is that the records would be at St. Mary's Catholic Church in Bismarck. I found my ggparents' marriage record in 1879, and subsequent children born through the 1880s. I don't know if the records are transcribed anywhere, but I looked through the actual records. They are all in Latin, so you would have to brush up on your Latin to read the names (e.g. Guillimus for William. etc.) The amazing thing is that even if couples moved away, they often brought their children back to Bismarck for baptism, and the church recorded their location, such as 80 m. from Bismarck on the Little Heart River. Good luck!