A Centers for Disease Control and Prevention survey shows California's uninsured rate is down to 8.1 percent.
The National Health Interview Survey reflects the state's uninsured rate at the end of 2015. It shows California is below the national average of 9.1 percent.
Adults living in states that have expanded Medicaid are less likely to be uninsured, according to the survey.
Through the Affordable Care Act, California expanded Medi-Cal, the state's Medicaid program, and created a state-based health insurance exchange, Covered California.
In a press release, Peter V. Lee, executive director of Covered California, said millions of people have benefitted from the two programs.
"California is succeeding in this new era of health care by using all the tools of the Affordable Care Act-- expanding Medi-Cal and launching a state-based exchange that brings quality and value to our consumers," he said.
Currently, more than 12 million people are enrolled in Medi-Cal and about 1.57 million are enrolled in Covered California.