Copper Beech Farm in Greenwich, CT, which is listed at $190 million. (Christie's International Real Estate)

Its streets peppered with Wall Street hedge fund types, Greenwich, Conn., has long been associated with wealth, excess and luxury living.

But a new real estate listing in the area is taking the tony town's reputation to a whole new level. With a staggering asking price of $190 million, Greenwich's Copper Beech Farm is thought to be the most expensive home on the U.S. market.

But while the 12-bedroom French-renaissance, Victorian mansion (complete with two private islands) might be the pinnacle of luxury real estate, it is by no means an orphan in the ultra high-end housing market.

The luxury housing market is booming in hot markets across the country, with some even beginning to rival high-net-worth hubs such as London in popularity among the world's super rich. That's especially true among international buyers, among whom having a princely palace stateside is becoming just as important as having a pied-a-terre in Paris.

"It's not like every single home is sold to a Russian oligarch, but the reality is that depending on the market, at the ultra-high end you are finding international buyers," says Budge Huskey, president and CEO of Coldwell Banker. "There are great values here when you consider other markets like London, Tokyo, and Mumbai."

Targeted efforts by the Federal Reserve to coax the United States from its economic malaise have also played a role in boosting the luxury real estate market. Thanks to Fed policies, which have kept interest rates hovering near all-time lows for the past several years, those with financial assets in investments – mostly the wealthy – have turned to the stock market for better returns. As the economy has improved, so has the performance of many stock market sectors, fueling an unprecedented restoration of wealth.

"Many of these people are back where they were before [the financial crisis] if not even further along," Huskey says. "They're in a financial position to act."

But having the cash on hand hasn't necessarily been the problem for many who are now paying millions for ultra-luxury abodes. In recent years, spending enormous sums of money while thousands of Americans lost their jobs and the economy sputtered seemed "gauche," according to Huskey, leading those who had the means to buy to hold off on purchasing such pricey pads.

That's changing now as the economy recovers, along with the typical profile of the luxury buyer. According to Huskey, where buyers on the higher end of real estate spectrum used to be older retirees, more recently the average age has dropped, settling in the 30 to 50-year-old range.

The shift in age has also ushered in a shift in preferences, he says, with many younger buyers preferring functional space that focuses on family over things like formal living and dining rooms.

"The lifestyle of these people are very different – they're not looking for a grand formal environment," Huskey says. "The best description I could give is that they want a luxury kids camp where their kids can be around them, not banished to a basement rec room."