Medicaid is the federal health insurance program that covers people who have low-incomes and meet certain categories of eligibility. Medicaid eligibility varies by state.
The Affordable Care and Patient Protection Act (ACA) created a new category of eligibility for the Medicaid program to include individuals who have incomes at or below 138% of the Federal Poverty Level (FPL). Due to the Supreme Court decision in National Federation of Independent Business v. Sebelius (2012), states have the option to expand their Medicaid programs.
This chart shows what each state is doing.