Often, counties with the lowest literacy rates are the same areas that experience poor health, poverty, and low economic mobility.
There is a strong regional divide. The Midwest and Northeast have much higher and more regionally consistent literacy rates. In the South and West, literacy rates can vary widely from county to county.
There has not been a comprehensive survey focused specifically on adult literacy in the United States since 2003. Although more recent surveys have asked about adult skills and education, data on adult literacy remains sparse.