The nation's poorest families are covered by the government-run Medicaid and Medicare programs. Those who earn too much to qualify for Medicaid but less than 400 percent of the poverty level — $45,000 for an individual and $94,000 for a family of four — can receive premium subsidies for insurance purchased through the online exchanges. Bailey said the subsidies are more likely to benefit rural residents because they are less likely to have health insurance through their employers than people living in urban and suburban areas.

Most farmers buy their own insurance, and other rural residents often are self-employed or work for small businesses that don't provide group coverage, he said.

Roger Johnson, president of the National Farmers Union and a former North Dakota agriculture commissioner, said for many years the leading cause of farm bankruptcies was medical bills because many farmers couldn't afford to buy individual policies. Others opted for less expensive policies with high deductibles that Brock Slabach, senior vice-president for member services at the National Rural Health Association, said sometimes wasn't much better than having no insurance at all.

"I see that all the time, farm families who have to work a second job so that they can provide insurance to their families," Slabach said.

The health care law will help these families even if they don't qualify for premium subsidies because they'll be able to buy individual policies at rates comparable to group plans, he and Johnson said.

Wisconsin and Nebraska are among the states with Republican governors who opted not to create state-run exchanges and will be served by ones run by the federal government. The states have released the names of insurance companies that will offer plans through the exchanges, but as yet have provided no details about rates or plans.

Low-income families also could benefit from another provision in the health care law that caps out-of-pocket costs, the report said. For example, most people who buy a "silver" health care plan may pay up to $6,350 for medical expenses. But those earning up to about $23,000 per year would pay only $2,250 with the same plan.

The Center for Rural Affairs has received many calls from people who want to know what they would pay for insurance under the exchange, Bailey said.

"Every family, every individual is going to be a little bit different because of their circumstances," he said. The best advice, he said, is "when people have the opportunity, starting Oct. 1, take your time, research what's offered in your state and what works best for yourself and your family and what it costs and what works best for your pocketbook and your health care needs."