Federal frame
The federal gambling laws that still matter: Wire Act and UIGEA
The short answer
The Wire Act (1961) prohibits using wire communications for bets on sporting events across state lines; UIGEA (2006) blocks financial transactions tied to unlawful internet gambling but creates no legality itself — it defers to underlying state and federal law. The pivotal document is DOJ's 2011 OLC opinion limiting the Wire Act to sports wagering, which opened the door to state-licensed online casino and lottery products; a 2018 reversal attempt failed in court, and the 2011 reading still governs today's iGaming market.
In this article
US gambling law is mostly state law — but two federal statutes sit underneath everything online. Understanding them explains both why the market looks the way it does and why its legal walls are where they are.
The Wire Act: 1961's wire-fraud law
Passed to attack organized bookmaking, 18 U.S.C. § 1084 makes it a crime to use wire communications to send bets or wagering information on 'any sporting event or contest' across state or national lines. For half a century its scope was read broadly — as covering essentially all internet gambling — because the internet is, literally, wires across state lines.
UIGEA: payments, not gambling
- The 2006 Unlawful Internet Gambling Enforcement Act never declares which gambling is unlawful — it borrows the answer from other federal and state law.
- Its operative provision, 31 U.S.C. § 5363, prohibits gambling businesses from accepting payments connected to unlawful internet bets.
- Compliance duties fall on banks and payment processors: they must screen for restricted transactions.
- UIGEA includes carve-outs — for intrastate wagering, for transactions between permitted jurisdictions, and (famously) for fantasy sports meeting its conditions.
The 2011 opinion that built the market
In 2011, the DOJ's Office of Legal Counsel answered a question from Illinois and New York: could state lotteries sell tickets online if data crossed state lines? The opinion concluded that interstate wire transmissions unrelated to a sporting event fall outside the Wire Act — the statute's sports-specific reading controls. That single document legalized the logic of state-licensed online lottery and, by extension, online casino: if the Wire Act only reaches sports wagering, non-sports iGaming was a matter for state law. The DOJ reversed the opinion in 2018, but the First Circuit declined to apply the broader reading in the New Hampshire lottery litigation, and the 2011 framework remains the operative one in 2026.
The state map that grew inside this frame: where online casino is legal, the geolocation machinery enforcing it, and the adjacent regime testing the boundary in prediction markets vs. sportsbooks.
