There are 50.7 million uninsured Americans as of the 2010 census, and in some states, over a quarter of the population is uninsured.

States in the South and Southwest make up the majority those with the highest share of residents with no health insurance, according to the recently released Small Area Health Insurance Estimates by the U.S. Census Bureau. The study was based on demographic population estimates, federal tax returns and Medicare and Medicaid participation records, as well as other sources.

While Republican Senate leader Mitch McConnell recently called the tens of millions of uninsured Americans “not the issue,” not having health insurance can prove both tragic and fatal. A 2009 study showed that uninsured patients are twice as likely to die during emergency room visits.

The plight of uninsured Americans also was brought into sharp relief this summer following the shooting massacre in Aurora, Colo., when it was estimated that uninsured victim Caleb Medley faced $2 million worth of medical costs.

But with the Supreme Court's upholding of the Affordable Care Act in June, millions more Americans will gain access to health insurance once the law is fully implemented. Already, it's estimated that 6.6 million young adults now have health care coverage due to the law.

Here are the states with the most uninsured residents:

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  • 10. California

    <strong>Share of uninsured:</strong> 20.7 percent <strong>Number uninsured:</strong> 6,720,279 <strong>State population:</strong> 32.504,288

  • 9. Montana

    <strong>Share of uninsured:</strong> 20.7 percent <strong>Number uninsured:</strong> 170,509 <strong>State population:</strong> 823,852

  • 8. Mississippi

    <strong>Share of uninsured:</strong> 21 percent <strong>Number uninsured:</strong> 525,570 <strong>State population:</strong> 2,504,200

  • 7. Alaska

    <strong>Share of uninsured:</strong> 21.4 percent <strong>Number uninsured:</strong> 138,777 <strong>State population:</strong> 647,241

  • 6. Oklahoma

    <strong>Share of uninsured:</strong> 21.9 percent <strong>Number uninsured:</strong> 691,408 <strong>State population:</strong> 3,163,465

  • 5. Georgia

    <strong>Share of uninsured:</strong> 21.9 percent <strong>Number uninsured:</strong> 1,848,505 <strong>State population:</strong> 8,435,908

  • 4. New Mexico

    <strong>Share of uninsured:</strong> 22.6 percent <strong>Number uninsured:</strong> 397,890 <strong>State population:</strong> 1,756,794

  • 3. Nevada

    <strong>Share of uninsured:</strong> 25.1 percent <strong>Number uninsured:</strong> 589,059 <strong>State population:</strong> 2,346,884

  • 2. Florida

    <strong>Share of uninsured:</strong> 25.3 percent <strong>Number uninsured:</strong> 3,853,392 <strong>State population:</strong> 15,210,949

  • 1. Texas

    <strong>Share of uninsured:</strong> 26.3 percent <strong>Number uninsured:</strong> 5,820,793 <strong>State population:</strong> 22,098,206

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