If you are buying health coverage in the Colorado ski resort towns, the Connecticut suburbs of New York City or a bunch of otherwise low-cost rural regions of Georgia, Mississippi and Nevada, you have the misfortune of living in the most expensive insurance marketplaces under the new health law.

The 10 most expensive regions also include Alaska and Vermont and large parts of Wisconsin and Wyoming. The ranking is based on the lowest price “silver” plan, which is the mid-level plan that the majority of consumers are selecting.

These regions, created as part of the health law, range in size from a state to a single county. While many people in these regions will receive government subsidies to help pay for the premiums, the portion that they will pay will still be higher than they would have to foot in many other places.

The causes of the stratospheric premiums vary from region to region, although a recurring theme is that in some areas the limited number of hospitals and specialists allows them to demand high prices from insurers. In Southwestern Georgia, one hospital system dominates the area and beat back an effort by federal anti-trust regulators to loosen its grip on the market. High individual insurance rates also reflect the extra costs that come when locals tend to be in poor health and where large numbers of people lack employer-sponsored insurance, leaving providers with more charity cases and lower-reimbursed Medicare patients.

A sicker population does not explain the most expensive region in the country: four mountain counties around Aspen and Vail. People here are generally healthy, but medical prices and the use of medical services are both high.

In Summit County, the average hospital inpatient cost was $786 per insured person, 61 percent above the state average, even though admissions were 10 percent below the state average, according to data from the Colorado All-Payer Claims Database. In Pitkin County, where Aspen is, costs from doctors and other medical professionals were $1,932 per insured person. That was 2.2 times higher than the state average even though the number of claims filed was 17 percent fewer.

The highest cost regions were determined by the monthly premiums for a 40-year-old person. The list is based on rates listed on the federal and state insurance marketplaces and data compiled by Kaiser Family Foundation researchers. (KHN is an editorially independent program of the foundation.) In each region, the price of every policy has to be consistent across all counties, although the insurer does not have to offer each policy in every county. When the least expensive silver plan is not offered in a county, Kaiser Health News notes the cheapest available silver plan there.

Here are the 10 most expensive regions:

$483: Colorado Mountain Resort Region. Eagle, Garfield and Pitkin counties, home of Aspen and Vail ski resorts. Summit County premiums are $462.

$461: Southwest Georgia. Baker, Calhoun, Clay, Crisp, Dougherty, Lee, Mitchell, Randolph, Schley, Sumter, Terrell and Worth counties.

$456: Rural Nevada Esmeralda, Eureka, Humboldt, Lander, Lincoln, Elko, Mineral, Pershing, White Pine and Churchill counties.

$445: Far western Wisconsin. Pierce, Polk and St. Croix counties, across the border from St. Paul, Minn.

$423: Southern Georgia. A swath of counties adjacent to the even more expensive region. Ben Hill, Berrien, Brooks, Clinch, Colquitt, Cook, Decatur, Early, Echols, Grady, Irwin, Lanier, Lowndes, Miller, Seminole, Thomas, Tift and Turner counties.

$405: Most of Wyoming. All counties except Natrona and Laramie.

$399: Southeast Mississippi. George, Harrison, Jackson & Stone counties. In Hancock County, the lowest price plan is $447.

$395: Vermont.*

$383: Fairfield, Conn. The southwestern-most county, which includes many affluent commuter towns for New York City.

$381: Alaska.

*Unlike other states, Vermont does not let insurers charge more to older people and less to younger ones. Its ranking therefore will differ depending on the ages of the consumers.

Sources: Kaiser Family Foundation Program for the Study of Health Reform and Private Insurance; healthcare.gov; state exchanges.