The top five states in the ranking were on the East Coast, including Connecticut, Washington, D.C., New York, New Jersey, and Massachusetts. California took the sixth spot.
Using IRS tax return data to make the ranking, SmartAsset looked at individuals and couples who earned at least $1 million in adjusted gross annual income. One of its conclusions was that states with higher cost of living tended to have more millionaires, saying that "Someone earning $847,457 in Minneapolis has the equivalent purchasing power of someone earning $1 million in San Francisco."
Just under 1 percent of American taxpayers filing from abroad had an adjusted gross income of at least $1 million, according to our analysis. If we had ranked Americans abroad as a separate region for this study, it would have ranked first. In fact a taxpayer filing from abroad is about 50 percent more likely to be a millionaire than a taxpayer from first-ranked Connecticut.