Under the Affordable Care Act (ACA), states can expand Medicaid eligibility for nonelderly adults with incomes up to 138 percent of the federal poverty level (FPL). As of May 2016, 19 states had not expanded Medicaid. Based on reported Medicaid and marketplace data, we estimate that in 2017, even without the Medicaid expansion, the major coverage provisions of the ACA will have reduced the numb...