Is polygamy allowed in the United States

Polygamy and polyandry are both illegal in the U.S., regardless of what this man (and the women) want.

A small portion of the Mormon (a religion) population do practice polygamy, but mostly in secret.

Of course if various numbers of genders which to reside together, no one can stop them, but they cannont legally marry in the U.S.

A lot of laws aren't really enforced. I'm quite sure everything you can imagine is going on somewhere. If you have money and power the laws often don't apply. It is fascinating to see how a man gets two or more women to share him.
I've seen whole television shows on the subject in regard to the Mormon community in Utah. Whether or not it's legal, it goes on. I'm not going to join the Mormon or Muslim Religion just to get in on this but it's a great recruitment tool. Candlelight8

Two wives... six chins.