Washington State has had a fairly healthy Obamacare exchange -- until now, that is.

Two counties won't have any insurers participating in the individual market -- either on the state's Obamacare exchange or off of it -- next year unless another company steps in, the Washington insurance department said Wednesday.

This could be trouble for the more than 3,300 people in those counties, Klickitat and Grays Harbor, who buy their own coverage. This includes the more than 2,100 residents who signed up for policies through the exchange.

Washington would become the third state to have locales without any Obamacare insurers. Enrollees in the Kansas City, Missouri, area and in parts of Ohio also won't have any options on their exchanges next year unless other carriers join.

Related: Anthem pulls out of Obamacare in Ohio for 2018, citing uncertainty

The development in Washington, however, is surprising because the state is one of the few to run its own marketplace, and officials are very supportive of the health reform law. Nine insurers are offering coverage on the exchange this year. That figure will drop to six in 2018, but that's still more than in many other states.

"The Affordable Care Act has worked in Washington state because we fully embraced the reforms it offered -- including expanding Medicaid and creating our own state exchange," said Insurance Commissioner Mike Kreidler, who added that he will reach out to the state's insurers to "strongly encourage them to reconsider."

Washington's embrace of Obamacare has "helped increase competition, provided better coverage and access, and fueled the largest drop in our uninsured in decades," said Kreidler, striking a different tone than officials in some other states, who blamed flaws with Obamacare for insurers' withdrawals or requested rate hikes.

The state won't release next year's rate requests by the remaining insurers until later this month. But carriers who pulled out cited the expense of setting up doctor and hospital networks or the ongoing uncertainty surrounding Obamacare's future, a department spokeswoman said.

Both the commissioner and the state exchange's CEO blamed President Trump and Republicans in Congress for fueling problems. Insurers are mainly concerned that the White House is undermining the individual mandate, which requires nearly all Americans to buy coverage, and won't commit to continue funding the cost-sharing subidies that reduce deductibles and co-pays for lower-income Obamacare enrollees.

Related: Trump, Congress punt again on critical Obamacare subsidies

"While we are seeing a number of carriers returning this year, we also were dismayed by the role federal uncertainty played into the decision of others to discontinue offering products or scale back their existing service areas," said Pam MacEwan, CEO of the Washington Health Benefit Exchange.

Even though the bill to repeal and replace the Affordable Care Act is working its way through the Senate, Obamacare still remains the law of the land. Insurers are now telling state regulators whether they'll participate for 2018 and the rates they want to charge consumers.

How Obamacare is faring nationwide really depends on the state -- and even the county. Insurers are pulling out of some areas, leaving a growing number of places with only one carrier on the exchange. Humana (HUM), Aetna (AET) and several Blue Cross and Blue Shield plans, which specialize in the individual market, have announced their departures.

Related: Anthem pulls out of Obamacare in Ohio for 2018, citing uncertainty

In some states, including Maryland, Virginia and North Carolina, insurers are filing for big rate hikes for 2018, fueled in part by the lack of clarity in Washington D.C.

But elsewhere, the market is doing better. Several insurers have said they've staunched the bleeding they experienced in recent years from sicker-than-expected policyholders, thanks partially to large premium increases last year. That's leading carriers to request smaller bumps for 2018.

In New York, insurers have requested an increase of 16.6%, on average based on their relative enrollment. The filings were based mainly on rising medical costs, particularly for prescription drugs, an aging population and a broadening of the provider network. The state also asked insurers to estimate the impact of the potential repeal of the individual mandate and the loss of the cost-sharing reductions. Carriers responded it would cause rates to soar 34%.

Meanwhile, the five carriers participating on the state-run Pennsylvania exchange are asking for an average boost of 8.8%.

"These low percentages show that Pennsylvania's market is stabilizing and insurers are better understanding the markets and the population they serve," Insurance Commissioner Teresa Miller said.