St. John's Block Commercial Exchange is a Richardsonian Romanesque building in Grand Forks, North Dakota, United States. It is a five-story brick and ashlar building, built during 1890–1891. It is smaller than one acre. It was listed on the National Register of Historic Places (NRHP) in 1982. It was included in a 1981 study of Downtown Grand Forks historical resources that led to a large number of NRHP listings.