I put Puerto Rico in the "Caribbean" category. There are many islands off the east coast of the Americas with casinos and although not all are strictly in the Caribbean Sea, I find that a useful way to categorize these collectibles. Islands would be:

Puerto Rico
Aruba
Dominican Republic
St. Martin
Cuba
Bonaire
Curacao
Turks and Caicos
Antigua
St Kitts
Bahamas
St. Croix

You might want to use this category to avoid the question of whether P.R. chips are really US domestic chips.

By the way, I don't know of any current casinos in the U.S. Virgin Islands, but understand there is one in the planning stages.