The E. Janssen Building at 422 First Street, Eureka, California, is a two-story Italianate commercial building. It was built in 1875 to be a hardware and general merchandise store. In 1973 it was the first building in Eureka to be placed on the United States National Register of Historic Places, and it was listed as a contributing property of the National Register Old Town Eureka Historical District in 1991. The building has housed an art gallery since 1998.