We know that about 10 million more people have insurance coverage this year as a result of the Affordable Care Act. But until now it has been difficult to say much about who was getting that coverage — where they live, their age, their income and other such details.

Now a large set of data — from Enroll America, the group trying to sign up people for the program, and from the data firm Civis Analytics — is allowing a much clearer picture. The data shows that the law has done something rather unusual in the American economy this century: It has pushed back against inequality, essentially redistributing income — in the form of health insurance or insurance subsidies — to many of the groups that have fared poorly over the last few decades.

The biggest winners from the law include people between the ages of 18 and 34; blacks; Hispanics; and people who live in rural areas. The areas with the largest increases in the health insurance rate, for example, include rural Arkansas and Nevada; southern Texas; large swaths of New Mexico, Kentucky and West Virginia; and much of inland California and Oregon.

Another Map!

Each of these trends is going in the opposite direction of larger economic patterns. Young people have fared substantially worse in the job market than older people in recent years. Blacks and Hispanics have fared worse than whites and Asians. Rural areas have fallen further behind larger metropolitan areas.

Women are the one modest exception. They have benefited more from Obamacare than men, and they have received larger raises in recent years. But of course women still make considerably less money than men, so an economic benefit for women still pushes against inequality in many ways.

The Affordable Care Act was passed in 2010, but the law’s biggest insurance expansion provisions went into effect in January, when millions more people qualified for state Medicaid programs, and new subsidized insurance plans sold in state marketplaces kicked in.

All Uninsured Rate

Over all, about 10 million Americans who had no insurance in 2013 signed up for it this year, according to the Enroll America/Civis model. The groups estimate that the national uninsured rate for adults under 65 fell to 11 percent from 16 percent. (Because of the federal Medicare program, which provides universal coverage to Americans over 65 who meet certain basic requirements, more than 98 percent of that group has health insurance.)

Other estimates, including those from Gallup and the health research group the Commonwealth Fund, show higher uninsured rates but a similar reduction in the number and percentage of Americans without insurance. Enroll’s data analysts said their survey appears to have undercounted the uninsured a bit in both years, because they interviewed a smaller number of Hispanics, men and people with low incomes than the census measured. Those people are less likely to be insured, but were also harder for Enroll to reach because they have smaller digital footprints than other groups.

Below are several charts that help explain who was helped most by the passage of the Affordable Care Act.

Medicaid Expansion

That state boundaries are so prominent in the map attests to the power of state policy in shaping health insurance conditions. The most important factor in predicting whether an American who had no insurance in 2013 signed up this year was whether the state that person lives in expanded its Medicaid program in 2014. (Just consider the contrast between Kentucky, which expanded Medicaid, and Tennessee, which did not.)

In 2012, the Supreme Court gave states the right to opt out of the expansion. In all, 26 states and the District of Columbia expanded Medicaid programs this year, and at least one more state — Pennsylvania — will expand next year. Predominantly, the states that expanded had Democratic political leadership, while those that declined were governed by Republicans, but there were exceptions in both directions.

Race

Blacks and Hispanics entered this year with higher uninsured rates than whites and Asians. That’s still true, but they have also shown substantially larger gains. Matthew Saniie, the director of analytics and data at Enroll, said he attributed the racial trends to two main factors: existing high uninsured rates for those groups, and disproportionate poverty, meaning more people who qualify for Medicaid. In the case of Hispanics, he also said that California’s huge outreach effort, strongly targeted at its Latino population, gave the group another strong enrollment boost.

Age

Critics of the Affordable Care Act have often warned that the program would be unfair to the young because it limits the ability of insurance companies to charge higher rates to older customers, who tend to be sicker. But young adults show the largest reductions in being uninsured of any age group. And that’s not counting the approximately 3 million young adults who received coverage on their parents’ policies before 2014.

Income

People with the lowest incomes tended to benefit the most from the law. That makes sense, given how the Affordable Care Act is designed. In states that expanded Medicaid, low-income people can get insurance without having to pay a premium. And for middle-income people who qualify for tax credits to help them buy insurance, the subsidies are most generous for those lowest on the income scale. Poorer people were always the least likely to have insurance because their jobs rarely offered it and private premiums were often unaffordable.

Gender

Women were more likely to have insurance before this year, a reflection of existing state Medicaid policies, which offered coverage to pregnant women and mothers, but not childless adults. But that existing gender gap is widening. Professionals doing insurance outreach said that women were often easier to reach and more concerned about access to health care than men.

Politics

Despite many Republican voters’ disdain for the Affordable Care Act, parts of the country that lean the most heavily Republican (according to 2012 presidential election results) showed significantly more insurance gains than places where voters lean strongly Democratic. That partly reflects underlying rates of insurance. In liberal places, like Massachusetts and Hawaii, previous state policies had made insurance coverage much more widespread, leaving less room for improvement. But the correlation also reflects trends in wealth and poverty. Many of the poorest and most rural states in the country tend to favor Republican politicians. Of course, the fact that Republican areas showed disproportionate insurance gains does not mean that only Republicans signed up; there are many Democrats living in even the most strongly Republican regions of the country.

Where People Live

People who lived in rural areas were more likely to gain insurance than those living in big cities.

Prior Insurance

Over all, the changes tended to be strongest among the groups that were the least likely to be insured. The single most predictive question in the Enroll model for 2014 was whether someone was insured in 2013. That also means that the newly insured are not substantially different from the remaining uninsured in broad demographic terms. There are still a lot of uninsured people remaining, many in the places that had high uninsured rates last year.

Who remains uninsured in 2014

10% 12% 14% 16% uninsured

Overall uninsured

Enroll and Civis’s data is the output of a statistical model based on a large survey of adults. That means that the numbers are estimates rather than actual observations. For now, Enroll’s broad numbers line up with the findings of existing surveys. Next year, the census will be able to provide a similarly detailed picture of the uninsured in America, using less complex methods. Though Civis’s background is in political campaign outreach, the groups have little incentive for bias because skewed numbers would complicate efforts to find the uninsured and target outreach resources. For more about the methodology of the project, read our companion story here.