The last potentially empty county on the Affordable Care Act's insurance exchanges has landed an insurer, the Ohio Department of Insurance said Thursday.

CareSource, an Ohio-based insurer with a background in Medicaid, will offer plans on the ACA's individual insurance exchange in Paulding County, which was the last remaining county in danger of having no insurer in next year's marketplace.

The prospect of empty counties has long been a serious concern of health-policy experts, since there was no backup plan for those with coverage if counties went bare. This year, 334 people signed up for health insurance in Paulding County in the individual exchange established by the ACA, the healthcare law better known as Obamacare. Those people were at risk of losing their insurance next year if no insurer entered the market.

"There is a lot of uncertainty facing consumers when it comes to health insurance and these announcements will provide important relief," Jillian Froment, the Ohio Department of Insurance director, said in a statement Thursday.

Cynthia Cox, an associate director at the Kaiser Family Foundation, a nonpartisan health-policy think tank, said the concern was exacerbated in rural counties like Paulding because of the exit of Anthem and other Blue Cross Blue Shield providers.

"The majority of these counties were at risk of being bare at least in part because Anthem or the state’s Blue Cross Blue Shield plan left the market," Cox told Business Insider in an email. "These exits raised the question as to whether any company would have the ability or desire to come in and cover these counties. Not every insurer has a statewide provider network in place, and a lot of these counties are rural."

Many of the insurers that have entered bare counties in places like Nevada, Wisconsin, and Indiana over the past two months, Cox said, have been Medicaid-focused companies like CareSource and Centene that have experience serving populations that are more similar to exchange participants.

"At the end of the day, this is a business decision, and it appears Centene and several other companies see this market as profitable," Cox said. "First-quarter insurer financial data suggests that companies in the individual market are on a path to be profitable this year."

Kansas, Tennessee, and Washington were also among states recently in danger of having bare counties but eventually saw them filled.

Since President Donald Trump took office, the Department of Health and Human Services and Republican politicians consistently cited the bare counties as evidence that Obamacare was failing.

For Cox, however, this was an example of their deficiency — but also their resiliency.

"The exchange markets have not been without problems, but they aren't collapsing," Cox said.