The Unlawful Internet Gambling Enforcement Act of 2006 makes it illegal to operate an online gambling website anywhere in the US. But, it doesn't make it illegal for individuals to place wagers on an online gambling website.
The Department of Justice maintains that, under the Wire Act, all Internet gambling by bettors in the United States is illegal. U.S. House of Representatives Committee on the Judiciary Hearing on Establishing Consistent Enforcement Policies in the Context of Online Wagers, 110th Cong., Nov.