Taxpayers in rural, poor parts of the U.S. are more likely be audited by the Internal Revenue Service than those living in wealthier counties, according to a new analysis. The county where residents are most likely to face an audit: tiny Humphreys County, Mississippi, where the median household income is less than $24,000 a year, or less than half the income of a typical U.S. family. The higher audit rates in poor regions comes down to an IRS policy of scrutinizing taxpayers who claim the Earned Income Tax Credit, or EITC, a refundable tax credit aimed at low- and moderate-income Americans. Counties with higher-than-average audit rates tend to be located in the South, the northern Plains, Mountain and Western states. The upper Midwest, Mid-Atlantic and New England states have lower audit rates. Many of the counties with the highest IRS audit rates have larger minority populations. That includes Humphreys, where 3 of every 4 residents is black. By comparison ... Denali, Alaska, with the lowest audit rate of all U.S. counties, is 84 percent white and has a median household income of more than $83,000. Audit rates for millionaires have declined by half since 2010. Corporate audits are also on the wane. But the audit rates for people who claim the EITC hasn't fallen as sharply as for the rich and corporations, ProPublica reported in December. That means a typical EITC claimant, who earns less than $20,000 per year, is more likely to face an audit than a millionaire.