In 1987, a pair of academics at Rutgers University proposed their controversial “Buffalo Commons” idea that demographic and economic trends were emptying large swaths of the Great Plains and that much of the prairie should be turned into a huge reserve where the buffalo roam and the deer and the antelope play. And it was North Dakota, perhaps more than any other affected state, that was the poster child for the declining fortunes and depopulation of the plains.

Fast-forward to the present, and thanks to the oil wealth of the Bakken formation and the fracking boom in the western part of the state, North Dakota’s population is growing and it’s now gushing with millionaires. According to Phoenix Marketing International, the Peace Garden State last year was the biggest gainer in an annual ranking of states based on millionaires per capita––jumping 14 spots to 29th on the list.

Other big gainers in 2013 were Maine (up 11 spots to 25th) and Louisiana (up 10 spots to 32nd). The biggest losers were Nevada (down 20 spots to 39th) and Arizona (down 13 spots to 34th). Florida, Michigan and Idaho (all of which rank in the bottom 40% of the overall list), each dropped 10 spots.

The results from Phoenix Marketing, a global marketing services firm in Rhinebeck, N.Y., were part of its Global Wealth Monitor, a service that tracks affluent and high-net-worth households in the U.S., Canada and Europe. It found that Maryland was tops in millionaires per capita, followed by New Jersey, Connecticut, Hawaii and Alaska. Alaska entered the top five for the first time by booting out Massachusetts, which dropped from fifth to sixth.

According to Phoenix Marketing, the number of households with $1 million or more in liquid wealth was more than 6.1 million last year, up 0.87% from 2012.