[2] The four-floor, 76-room hotel was named after the Soo Line Railroad which had arrived in town in 1902 and whose depot was located several blocks away.

Beebe had previously designed the Patterson Block for him, also listed on the National Register and located around the corner from the Soo on Main Street.

[3] The building originally sported a tall brick pediment stating the name of the hotel and the date of construction but this was removed sometime after the 1930s.

When completed in early 1907 the building was advertised as "absolutely fireproof" recalling the fire that had destroyed most of downtown Bismarck in 1898.

The upper floors remained vacant until it was renovated in the 1980s by Northwest Development Group headed by Jim Christianson, who has restored many historic buildings in the Bismarck/Mandan area.