Objective Examine the ACA Medicaid expansion effects on Medicaid take‐up and private coverage through 2015 and coverage disparities by age, race/ethnicity, and gender. Data Sources 2011–2015 American Community Survey for 3,137,989 low‐educated adults aged 19–64 years. Study Design Difference‐in‐differences regressions accounting for national coverage trends and state fixed effects. Principal Findings Expansion effects doubled in 2015 among low‐educated adults, with a nearly 8 percentage‐point increase in Medicaid take‐up and 6 percentage‐point decline in uninsured rate. Significant coverage gains were observed across virtually all examined groups by age, gender, and race/ethnicity. Take‐up and insurance declines were strongest among younger adults and were generally close by gender and race/ethnicity. Despite the increased take‐up however, coverage disparities remained sizeable, especially for young adults and Hispanics who had declining but still high uninsured rates in 2015. There was some evidence of private coverage crowd‐out in certain subgroups, particularly among young adults aged 19–26 years and women, including in both individually purchased and employer‐sponsored coverage. Conclusions The ACA Medicaid expansions have continued to increase coverage in 2015 across the entire population of low‐educated adults and have reduced age disparities in coverage. However, there is still a need for interventions that target eligible young and Hispanic adults.