Posen is a village in Cook County, Illinois, United States. Posen is the German-language name for the western Polish city of Pozna?. The population of the village was 5,987 at the 2010 census.
The area that is now Posen was settled by farmers, mainly of Dutch and German origin, in the second half of the 19th century. In 1893 a Chicago-based real estate firm hired 75 agents in the Polish-speaking areas of Germany to sell land to Poles seeking to emigrate to the United States. Over the next few years the village emerged as a place largely inhabited by factory workers.In the 1930s the population of Posen was 98% of Polish origin.While as late as 2004 the Encyclopedia of Chicago still referred to Posen as "predominantly Polish American"even then an actual examination of the 2000 census ancestry report would have shown that only a quarter of the population claimed to have Polish ancestry.