I had no idea Chicago had a giant Polish population. From Poland Must Decide on EU, But How Will Chicago Vote?:
More than 800,000 Chicago-area residents have roots in Poland. Only Warsaw has a bigger Polish population, immigrants here are fond of bragging. The Polish Yellow Pages for the Chicago area runs to 1,672 pages. Delicatessens alone fill 29 pages. Chicago has Polish jazz clubs, Polish art galleries and a Polish orchestra. Even the newest immigrants find it relatively simple to find work in Chicago’s large network of Polish construction companies, cleaning services and retail shops.