That beats the forecast by 1 million people and caps a remarkable comeback from a disastrous rollout last fall that gave rise to predictions the law would collapse in its maiden year.
Instead, the health law, often called Obamacare, has helped bring about the largest increase in insurance coverage in the U.S. in half a century.
“This thing is working,” Obama said from the
California alone signed up more than 200,000 consumers for coverage in the last two weeks, the state announced Thursday, bringing the state's first-year total to nearly 1.4 million people, many more than any other state.
Millions more Americans have signed up for health insurance without using the marketplaces, including through Medicaid, employers or directly from insurers. That has helped to dramatically drive down the nation's uninsured rate, according to a growing number of national surveys.
Estimates of the total gain in insurance coverage nationally are still preliminary. And enrollment is continuing on several state insurance marketplaces, which have extended their deadlines past the April 15 date used by California and the marketplaces operated by the federal government in 36 states.
But new Gallup survey data released this week suggest that as many as 12 million previously uninsured Americans have already gained coverage since last fall.
Just 12.9% of adults nationally lacked coverage in the first half of April, initial data from the Gallup-Healthways Well-Being Index indicate. That's down from 18% in the third quarter of 2013, just before Americans could start shopping for coverage on the new online marketplaces created by the law.
Substantial obstacles still confront the health law.
Obama administration officials are working with state and insurance industry officials across the country to head off any big rate hikes next year, which could drive away many consumers.
Senior administration officials, including the president, met Thursday at the White House with insurance regulators and insurance executives to discuss the issue.
In California, state leaders are also wrestling with ways to assure that marketplace plans offer consumers access to an adequate number of doctors and hospitals.