In 2011 California enacted a demonstration project, the Low Income Health Program (LIHP), as an “early expansion” of Medicaid under the Affordable Care Act (ACA). We use the 2008-2012 American Community Survey (ACS) to assess the program’s coverage effects on adults 19-64 years and children 0-18 years with incomes below 200 percent of the federal poverty line. We use a difference-in-differences analysis comparing coverage type and uninsurance in counties that expanded the LIHP in 2011 to those in California counties that did not. We find that California’s 2011 expansion produced significant increases in public coverage for low-income individuals, particularly Latinos.