There are 618,000 "millennial millionaires" in the United States, and nearly half of them live in California, according to a new report.

The Coldwell Banker Global Luxury and WealthEngine report found the population of rich millennials — those born between 1982 and 1996 — is growing.

"By 2030, millennials will hold five times as much wealth as they have today, and are expected to inherit over $68 trillion from their predecessors in the Great Transfer of Wealth" from their baby boomer parents, considered the wealthiest generation in history, CNBC noted.

Almost half, 44%, of the millennial millionaires are concentrated in California, the report found. New York ranks No. 2, and is home to 14% of the millennial millionaires.

The top ZIP code for young millionaires, though, is in Traverse City, Michigan (49685), where luxury homes start at $500,000, a bargain compared with Silicon Valley, where those homes start at around $2 million, the report found.

Besides California and New York, other popular states for rich millennials are Florida, Massachusetts, and Texas, all with 5%; Washington and New Jersey, with 4%; Virginia and Illinois, with 3%; and Maryland, with 2%.

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