Harrison is an 'L'subway station on the CTA'sRed Line in the Chicago Loop. The station opened on October 17, 1943, as part of the State Street Subway. In 2006, the KDR standard signage at Harrison was replaced by the newer Current Graphic Standard signage. On February 9, 2009, an auxiliary entrance at Polk Street that was closed in 1968 was reopened due to an increase of both business and residents living in the South Loop neighborhood. On April 14, 2014, the Polk Street auxiliary entrance was temporarily closed, reopening on May 25, 2014. Later the same year, the main entrance closed on June 16 and reopened on July 28.