Polymarket Montana: One of the Only States That Named the Product

Most states on this site have said nothing about Polymarket one way or the other. Montana said something. Senate Bill 555 took effect on October 1, 2025, and it rewrote the state's definition of “internet gambling” to explicitly reach prediction-market platforms — not by implication, the way an old statute like New Hampshire's might, but by design. That makes Montana one of the clearest bans in the country, even while the federal question underneath it is still being fought in court.

Is Polymarket Legal in Montana? Read SB 555 First

SB 555, signed by Gov. Greg Gianforte, broadens “internet gambling” to cover any platform, website or app that transmits or receives gambling information, takes a wager in any currency — crypto included — and makes a payout. That language was built to catch sweepstakes casinos and prediction markets in the same net. It exempts the state lottery, licensed simulcast wagering, and registered nonprofit raffles. It does not exempt Polymarket or Kalshi. Violations are felonies: up to $50,000 per offense and up to 10 years in prison for operators.

The Kalshi Fight Is the Test Case

Montana's Gambling Control Division, under Attorney General Austin Knudsen, sent Kalshi a cease-and-desist letter in March 2025 — before SB 555 even existed, under the state's older general gambling statute. The two sides wrote a non-enforcement truce a month later. Montana broke it on April 6, 2026, with a second cease-and-desist letter. Kalshi sued Knudsen in federal court days after that, arguing the Commodity Exchange Act preempts state enforcement against a CFTC-designated exchange. That case is unresolved, currently paused while settlement talks continue — nobody has won yet.

Where Polymarket Fits In

Nobody has published a Polymarket-specific cease-and-desist letter the way Montana did for Kalshi, and Polymarket has not filed a Montana lawsuit of its own. But SB 555 was never written around one company — it targets the category — and independent trackers following the 2026 state-by-state fight already list Polymarket as unavailable to Montana residents. Two different blocks stack here: the international polymarket.com site has been geo-fenced against every US IP since a 2022 CFTC settlement, unrelated to Montana law; Polymarket US, the QCX-run CFTC exchange, is the rail SB 555 and the Gambling Control Division are actually aimed at.

Is Polymarket Legit and Safe in Montana?

Legit: nothing about Montana's law questions whether Polymarket US honors a winning contract — it operates under the same CFTC designation, KYC and dollar settlement here as anywhere else. The dispute is jurisdictional. Safe: legally, Montana is a harder no than most states on this site, since SB 555 attaches felony exposure to unlicensed prediction-market activity rather than leaving the question open. Sports Bet Montana's consumer protections — Lottery licensing, geolocation, capped stakes — were built for a completely different, in-person product and don't extend to Polymarket either way.

A federal court could still rule that Montana can't enforce SB 555 against a CFTC-designated exchange at all — that is exactly what Kalshi's pending case is arguing. Until that resolves, Montana is not a state to treat casually. This is not a way to make money regardless of how the jurisdiction question shakes out. 21+ only; the Montana Council on Problem Gambling operates a confidential helpline for anyone who wants support.