Due to privacy issues, the U.S. Census Bureau is not releasing individual county data for any county with a population less than 50,000. This doesn't mean that there are counties missing from the data files, it just may be that a small indivdual county was combined with another. Groups of small counties were aggregated to create county sets of 50,000 or more so that all the counties are accounted for within each state. For more information on County Set naming guidelines click here.
To view a list of Micro SA's, select a state from the drop-down