Quora explanation from a Native American on the amazing number of Cherokees:

"And why is this inflated?

"Well, because there are more Americans - mostly Whites, but some Blacks - that claim to be “part-Cherokee” who have no such ancestry or affiliation, than their are legitimate Cherokees and Cherokee descendants. This bogus contingent usually has family lore that is not accurate at all. But, the claims are internalized to an amazing degree, and hundreds of thousands, and perhaps even into the low millions, of people make such claims.

"For just one example, half a million such people even took the time to write in “Cherokee” on the 20 Census. And that is not even including people that didn’t claim it on the Census, but might do so in certain social settings and conversation. At that time, the Cherokee population of all three Cherokee bands was just around ,000.

"So, this inflates the perception of the Cherokee population by a very wide margin - probably by several times the actual population figure."

by Sam Morningstar