I have downloaded two datasets: 2007-2011, as well as a 2011 only dataset. In both, the county variable is missing the FIPS county code for Cook County IL, which is the county I’m seeking this data for. Is data from the Voting and Registration supplement available for any years for Cook County IL? Thank you.
Unfortunately, Cook County is not available in the samples you are looking for, or any CPS sample. This is actually quite common. Only about 45% of all US counties are identifiable in CPS samples. For future reference, you can use the links on the variable description tab for COUNTY to check if specific counties are identifiable in specific samples. IPUMS CPS has many alternatives for geographic areas. One example is the METAREA. In the 2004-2012 Voter Supplement, METAREA code 1605=Chicago-Naperville-Joliet, IL-IN-WI.
I hope this helps.