If you're a 38-year-old Missourian living in Pemiscot County in the Bootheel, an Affordable Care Act "gold" insurance plan will cost you at least $418 per month, before subsidies. If you're a 38-year-old living in Kansas City, a similar plan will cost you about $263 per month.

Here's why:

Under the Affordable Care Act, (also known as Obamacare) insurance companies have a limited number of factors they can use to make premiums more expensive for consumers. Starting in January 2014, companies can only charge consumers differently based on age, family size, tobacco use and geography.

To regulate the geographic factor for premium prices, the U.S. Department for Health and Human Services worked with every state's insurance regulators to determine rate-setting areas within the state.

In Missouri, the federal HHS and the state's Department of Insurance, Financial Institutions and Professional Registration divided the 114 counties into 10 rating areas.

We've mapped the areas below. To give you a sense of how much the rates vary, we've compiled data on how much the cheapest plans per insurance level category in the ACA marketplace would cost for a 38-year-old Missourian (the median age in the state is 37.9), living in different rating areas. You can click on a county and see the number of different plans offered there, and the price of the cheapest option.

Map by Harum Helmy and Scott Pham. Data from Centers for Medicare and Medicaid Services and the Department of Health and Human Services. Hat tip to North Carolina Health News for the original idea.

In a letter, Missouri's insurance department said the rating areas were developed this way to regionally align consumers with the health care facilities and services they are likely to use. Take, for example, Ste. Genevieve County and St. Louis County. The counties were placed in the same geographic rating area partly because the St. Louis-based BJC Health Care facilities receive referrals from Ste. Genevieve County Memorial Hospital.

The prices among regions vary based on different factors. According to North Carolina Health News, rate-makers also take into account "the number of hospitals and medical providers in the region, how much competition there is among the various providers, the local cost of medical care, the number of people in the area and how sick or well they’ve been in the past."

Insurance plans offered in the ACA marketplace have to offer the same basic set of essential health benefits. The plans are divided into different levels (bronze, silver, gold...) based on how much a premium will cost every month and the portion a consumer pays after doctor visits and prescription. The bronze plan, for example, will have a cheaper monthly premium, but a patient will have to pay more for a hospital visit. A consumer with a gold plan will pay more expensive monthly premium, but will pay cheaper for a hospital visit. For more information, click here.

To be clear, the dollar amounts in the map don't mean an individual will actually pay that much for health insurance through the marketplace. The prices in the map don't include the amount of federal subsidies consumers can get to help pay for their premiums. Subsidies are available for those who make between 100-400 percent of the federal poverty level. To see whether you qualify for a subsidy and for how much, check out NPR and Kaiser Family Foundation's subsidy calculator here.

If you aren't 38 and want to check out how much an insurance plan in the ACA marketplace can cost you, check out the Department of Health and Human Services' data here.