The New York Times just published an article detailing changes in newly-insured people through the Affordable Care Act, otherwise known as Obamacare. Since passage of the ACA, people have become insured for a variety of reasons. Some gained insurance through expanded Medicaid coverage. The below map is from The Advisory Board Company and shows states that accepted and denied the ACA's Medicaid expansion.
The two maps do not coincide perfectly, but there are some correlations. Check out Arkansas, Kentucky, and West Virginia in relation to their non-Medicaid-expanded neighbors. Wisconsin, Pennsylvania, and Maine look similar on the first map for apparently different reasons.
What patterns do you see?