Is Kalshi Legal in California? Kalshi, Polymarket and Tribal Land

Sports betting is illegal in California. The Ninth Circuit opened its 16 September 2026 opinion by saying so: "In California, where sports betting is illegal, you can't place your bet." Kalshi and Polymarket US nonetheless offer sports event contracts to Californians, on the argument that a contract listed on a CFTC-registered exchange is a swap governed by federal law, not a bet.

No California court or regulator has ordered either venue to stop. The one California ruling so far is narrower than it is often described: two tribes are likely to win their claim that Kalshi's sports contracts break federal Indian gaming law when they are entered from tribal land. It does not cover the rest of the state.

The international site, polymarket.com, is a different product. It does not accept new trades from anywhere in the United States, California included, under Polymarket's own documentation.

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Blue Lake Rancheria and Chicken Ranch Rancheria of Me-Wuk Indians sued Kalshi and Robinhood, which distributes Kalshi's contracts, in the Northern District of California in July 2025 (No. 3:25-cv-06162). A third tribe, Picayune Rancheria of the Chukchansi Indians, left the appeal by agreement after oral argument. The district court refused a preliminary injunction.

On 16 September 2026 a Ninth Circuit panel of Chief Judge Murguia and Judges McKeown and Paez reversed in part (No. 25-7504). It held that the tribes are likely to show that Kalshi's sports contracts are class III gaming, that a contract entered by a user on tribal land is gaming located on Indian lands, and that Kalshi offers it in breach of the tribes' gaming procedures. It upheld the refusal to stop Kalshi's "Sports Betting [Is] Legal in all 50 States" advertising, and sent the case back for the district court to weigh the remaining injunction factors.

The Ninth Circuit's mandate issued on 8 October, according to the parties' joint report of 14 October. On 21 October Judge Jacqueline Scott Corley neither granted nor refused the injunction: she told the parties to discuss a stipulation on geofencing that would stay in place until the court orders otherwise, added Buena Vista Rancheria as a plaintiff, and set 4 November for an amended complaint and a case conference.

In the joint report Kalshi says it began geofencing the tribes' lands with GeoComply on 23 September. The tribes dispute that and allege that a trade was placed on a reservation on 2 October. Both are the parties' positions, not findings by the court, and no court-ordered geofence was in place when the 21 October order was made.

The state has taken sides in other states' cases without suing anyone itself. On 12 June 2026 Attorney General Rob Bonta joined 36 other attorneys general in a brief backing Ohio against Kalshi in the Sixth Circuit, which ruled for Ohio and Tennessee on 25 September. On 7 October he signed the states' brief asking the Supreme Court to hear New Jersey's case, and on 29 October he joined another 37-state brief, backing Utah against Kalshi in the Tenth Circuit. His office called that California's ninth multistate filing against Kalshi and similar companies.

The Legislature has not passed a prediction-market law. Bills on officials trading prediction-market contracts on nonpublic information (AB 1840) and on the Attorney General's power to investigate prediction-market wagering (AB 2446) were last acted on in committee in the spring, according to bill trackers; the Legislature's own site could not be read for this check. On 27 March 2026 Governor Gavin Newsom signed an executive order barring his appointees from using nonpublic state information to profit on prediction markets.

California is in the Ninth Circuit, which ruled for Nevada against Kalshi on 28 August 2026; the Third Circuit ruled the other way for New Jersey in April. Three petitions ask the Supreme Court to settle whether federal law displaces state gambling law for these contracts. Responses are due on 13 and 16 November 2026 in two of them; in the third, New Jersey's (No. 26-299), the response is due on 9 November, and Kalshi asked on 29 October, unopposed, to move it to 7 December.

On 19 October the CFTC put into force an interim rule keeping casino-style gambling products offered under a state or tribal gambling authorisation outside the definition of a swap, and separately proposed adding specified event contracts to that definition. The proposal's comment period closes on 18 November; neither measure settles the tribal case or a state's gambling law. The US guide follows the national picture.

• Kalshi and Polymarket US - They operate in California under their federal registration, and no state order stops them. That is a description of the current position, not a ruling that their sports contracts are lawful under California law.
• On tribal land - The Ninth Circuit's reasoning turns on where the user is when the contract is entered. It applies to the land of the tribes in the case, and the injunction itself is for the district court to decide.
• polymarket.com - It does not take new trades from the United States, and Polymarket's help page says using a VPN to get around that breaks its terms.
• Age and identity - Polymarket US's terms require users to be 18 or older, or older where local law sets a higher age, and to pass identity checks.

The Ninth Circuit opinion, the district court's 21 October order and 14 October joint report, the Attorney General's releases, the Supreme Court dockets, the CFTC's rules and the venue documents were read on 30 October 2026. District-court filings after 21 October were not available. Vultax did not test access from California or from tribal land.

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