Illinois is the only remaining state where concealed carry of firearms is illegal. This solely because of Chicago. Chicago's state legislature votes are the only reason why a statewide concealed carry law has a majority, but not the supermajority that it needs to be sent to the governor, a Chicago politician who has said that he will veto any such law.
Cook County, Illinois is the only county in Illinois that really wants significant restrictions on firearm ownership. However, the largest city in the midwest is in Cook County, and Cook County therefore exerts a huge level of influence over the state's politics. For this reason, state law still bans concealed carry of firearms even though a majority of state legislators voted to pass a bill allowing concealed carry, as the Illinois constitution would require a supermajority.
On Tuesday, March 20, 2012, Pike County passed a law allowing concealed carry of firearms by anybody without any sort of permit. This is thought to have been a significant contribution to the fact that it was one of the largest voter turnouts of any local-only election in US history. This was the first time that a county specifically voted to overrule state law since 1862 when five counties in the northwest of Virginia voted to nullify the articles of secession, forming West Virginia.
One of the common gun control talking points when discussing state laws versus local laws is that local governments (usually referring to Philadelphia or somewhere like that) should be able to make their own laws. However, the people who say that are almost definitely not going to say that Pike County has the right to do what they did, which is hypocritical.