The expression the collar counties is a colloquialism for the five counties of Illinois that border Chicago's Cook County. After Cook County, they are also the next five most populous counties in the state. According to the Encyclopedia of Chicago, there is no specifically known origin of the phrase, but it has been commonly used among policy makers, urban planners, and in the media. However, it also notes that as growth has spread beyond these counties, it may have lost some of its usefulness. The collar counties are tied to Chicago economically. However, like many other suburban areas in the United States, the collar counties have somewhat different political leanings from the core city. Chicago has long been a Democratic stronghold, while the collar counties historically tilted Republican. In recent elections, however, the collar counties have voted for Democrats, but with lower margins than Cook County. While the demographics of these suburban Chicago counties are fairly typical for American metropolitan areas, the term is apparently unique to this area. Also, because Cook County is so firmly entrenched in the Democratic column, and rural Downstate is overwhelmingly Republican, the collar counties are routinely cited as being the key to any statewide election. However, that conventional wisdom was challengedin 2010 as Democrat Pat Quinn won election as governor while only winning Cook, St. Clair, Jackson and Alexander counties. All five collar counties went Republican, so the key to winning that gubernatorial election was simply winning Cook County, but by a wide enough margin to overwhelm the rest of the state. While the term is often employed in political discussions, that is not its exclusive use. Barack Obama used the term in his speech before the Democratic National Convention in 2004. As of 2010 there are 3,143,257 people residing in the collar counties, nearly 25% of the population of Illinois. Combined with Cook County the area has approximately 65% of Illinois's population.
