If you are veteran online gambler from the United States, you likely already know about your Uncle Sam's wish to not allow you to gamble online - likely because they are not able to tax it, they have land-based casino lobbyist filling their pockets, and any number of other reasons none of which render you free to do what you want, in your own home, with your own money.
Despite those wishes only a handful of US States actually have laws that ban online "casino" gambling. At the federal level there are no laws that prohibit online "casino" gambling, though the infamous UIGEA was passed in the 11th hour of the day while everyone was rushing out the door by being attached to a must-pass Port Act Bill, it only restricts banking institution from handling the transactions.
As a result of this oppressive measure most of the online casinos pulled out of the USA. There are still a few that do business though and below is a listing of Slot Machines that are still available for play to USA Slot players.
If you are in the USA I recommend that you review your states laws prior to signing up at a casino to play one of these slot machines. However, if you know and/or find that your State does not have a law banning it, you should feel confident that these slot machines are being offerred by reputable casinos.