In suburban Cook County , regional groups , such as the Southland Democrats , co-ordinate activities with their local Democratic township organizations and their committeemen . Article IV , Section 4 of the By-laws of the Cook County Democratic Party allows the Suburban Vice-Chair ( a position currently held by Illinois State Senator Don Harmon ) the authority to " convene caucuses and meetings , solicit support for the organization , assist the County Chair in any matters upon request , coordinate activities concerning recommendations for endorsements of candidate , and bring before the Central Committee issues of particular interest . " Cook County was created on 15 January 1831 and it was named after Daniel Cook . Cook had been one of the earliest and youngest statesmen in Illinois history and he was a registered Democrat in Randolph County . By 1837 , local Democrats were winning electoral victories under the leadership of William B. Ogden . Ogden recruited Irish immigrants into the party . Their loyalty to native Democrats was established in return for petty political favors and an occasional elected office . The careers of Irish Democrats from this period , such as John Comiskey from the Blue Island area , were still limited by anti-Irish discrimination . Prior to the American Civil War , the city of Chicago and Cook County had created a strong two-party tradition . The local Democratic Party grew stronger in the decades that followed the Great Chicago Fire due in part to an influx of new immigrants from eastern and southern Europe . By 1890 , Roger Charles Sullivan had accumulated major influence within the tumultuous Cook County Democratic Party . He would come to dominate the organization for two decades and he was a national figure during the age when urban political bosses reached the height of their power and prestige . After his death , he was followed as chairman by George Brennan in 1920
Great Chicago Fire
Great Chicago Fire
Cook County Democratic Party