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.

In 2010, reflecting urban growth, the Bureau redefined the area as comprising several additional counties in Illinois, Indiana, and Wisconsin.

[6][7] Like many other suburban areas in the United States, the collar counties have somewhat different political leanings from the core city.

As Democrats began organizing in the area to appeal to suburban voters while Republicans turned towards conservativism, along with demographic changes, much of the politics of the counties shifted considerably.

[14] Barack Obama won all the collar counties in 2008, and four of them (all but McHenry) have voted for the Democratic nominee in every presidential election since.