Daniel Kálmán Biss (born August 27, 1977) is an American mathematician and member of the Illinois Senate from the 9th district, serving since January 2013. The district includes Chicago's northern suburbs, including Evanston, Glencoe, Glenview, Golf, Morton Grove, Northbrook, Northfield, Skokie, Wilmette, and Winnetka. Biss previously served in the Illinois House of Representatives from 2011 to 2013.