Situated along the west side of Main Street in Spearfish, The Mail Building is a two-story false-fronted commercial structure built of concrete or cast stone blocks. Typical for its time of construction, the material for the concrete mixture contains native sandstone giving the blocks a natural brown or tan color, which is in harmony with older buildings along Main Street (Spearfish Commercial Historic District) that are constructed of cut sandstone. This impression is supported by the "rusticated" pattern cast into the blocks. The two-story cast block structure is connected at the rear (alley side) to a newer, single story concrete block section, which is used as a small warehouse...
The Mail Building is significant in the area of communication, because from 1920 to 1932 it was the location of the community's foremost newspaper. Established in 1889, the Queen City Mail played an important communications role in the early years of Spearfish and continues to be the major newspaper in the immediate community to the present day. The Mail Building is the oldest extant reminder of this early newspaper enterprise.