Those living in Minnesota have an average score of 713, which falls into the "good" range of scores between 670 to 739, according to Experian. The company's annual State of Credit report and state ranking is based on Vantage Scores, which range from 300 to 850. South Dakota, Vermont, New Hampshire and Massachusetts round out the top five states with the highest average credit scores for 2018.

Minnesota residents can brag about more than their 10,000 lakes — they typically have the country's best credit scores too. As in previous years, the midwestern state has America's highest average credit score, according to Experian.

At the other end of the spectrum, residents in southern states had the lowest average credit scores. The lowest score, 652, belonged to those living in Mississippi. Louisiana, Nevada, Georgia and Texas are all in the bottom of Experian's ranking as well, with scores of 659 or below.

"The southern tier of the U.S. has historically had lower scores than the Midwest and the northern part of the country," Rod Griffin, Experian's director of consumer education and awareness, tells CNBC Make It. That said, he notes that it is difficult to pinpoint exactly why, saying that it's likely a mix of the economic environment and cultural norms.

While there is no single cause, the rate at which people in the South are using their available credit tends to be consistently higher than in other parts of the country, Griffin says.

"That, to me, is a telling issue. People may be using their credit cards as a supplement to their income in the South, or are just using them more and carrying a higher balance," Griffin says. Credit utilization, as it's called, is the ratio of money you have on your credit cards to the total amount of credit you have available. And it plays a big factor in calculating credit risk and therefore credit scores. When you use more than 30% of your available credit, your credit score is typically going to be lower because there's a greater risk you may not pay it all off, or that it may take a while to do so, he says.

Those living in Arkansas and Mississippi have the highest average credit utilization rates in the country at 36% and 35%, respectively.

But Griffin says it's important to keep in mind that these are average scores within each state, so while they provide insight generally, there are lots of individuals with really strong credit scores in all of these states.