Midterm Election Odds 2026 – House, Senate & Governor Races

Get the 2026 US midterm election odds as clean JSON: every 2026 House, Senate and Governor race Kalshi trades, plus which party controls the House and the Senate, with win probability, bid/ask, volume and a Polymarket comparison. Built for election forecasters, journalists, political analysts, traders and AI agents that need all the races in one table, without a login, API key or proxy. One run reads every open race, sorted by trading volume, so the biggest markets (chamber control, Texas, Maine, Michigan) come first.

What you get

• Every race in one run: chamber control plus all 435 House districts, Senate races including the special elections (Ohio, Florida) and Governor races, each outcome as a row with state, district, candidate and party.
• Real prices, not fake 50/50: probability is the midpoint of a real bid/ask, or the last trade when the spread is wide. Empty or settled markets get null instead of a made-up number.
• Kalshi vs Polymarket: House and Senate control rows carry Polymarket's price for the same party and the gap between the two.

Example row

{
  "rank": 4,
  "office": "senate",
  "state": "TX",
  "state_name": "Texas",
  "district": null,
  "race": "Texas Senate winner?",
  "outcome": "Ken Paxton",
  "party": "Republican",
  "probability": 0.38,
  "yes_bid": 0.37,
  "yes_ask": 0.39,
  "spread": 0.02,
  "last_price": 0.39,
  "volume": 9123538.01,
  "open_interest": 6141250.92,
  "polymarket_probability": null,
  "polymarket_gap": null,
  "market_ticker": "SENATETX-26-R",
  "event_ticker": "SENATETX-26",
  "series_ticker": "SENATETX",
  "close_time": "2027-11-03T15:00:00Z",
  "scraped_at": "2026-09-30T17:59:31+00:00"
}

Input

Field	What it does
offices	control, senate, governor, house. Empty = all four.
states	Two-letter state codes such as TX, PA, AZ. Empty = all states. Chamber control is kept when control is selected.
maxRows	Keep the top N outcomes by trading volume. Default 100.
minVolume	Skip thin markets below this many contracts traded.
includePolymarket	Add Polymarket's price to the House and Senate control rows. On by default.

rank is the position by volume among the outcomes that match your filters.

Pricing

Pay per event: $1 per 1,000 outcomes ($0.001 per outcome), plus a start fee of $0.001 per run. The default run (top 100 outcomes) costs about $0.10. Error rows, such as an unknown state code, are never charged. A run reads all open markets and takes roughly a minute.

Good to know

• Prices are Kalshi's regulated exchange prices, with no login and no proxy. probability is an implied probability from market prices, not a poll and not a forecast from this Actor.
• Coverage is what Kalshi lists as a "winner" market for 2026: House district races, Senate races (including the Ohio and Florida special elections), Governor races and chamber control. Primaries, nominee markets, turnout, margin-of-victory and seat-count markets are not included, and neither are Lieutenant Governor races. US territories and foreign races (for example in Brazil or Mexico) are not included. Races Kalshi does not trade are not in the data. Uncontested or very thin races can have wide spreads.
• A few races have two Kalshi markets, one by party and one by candidate (the race text ends in "(Person)" for the candidate version), so both appear.
• district is the House district number, and 0 means an at-large state such as Wyoming. party is empty for independents and other candidates the market does not label by party.
• close_time is when the market is set to close, which is after the election (settlement window).
• The Polymarket comparison covers House and Senate control only. For other races polymarket_probability is null.
• Candidate and party names are the public labels on the market. The Actor returns no profile data.
• Not affiliated with Kalshi or Polymarket.
• Schedule it daily, or hourly in the last week before November 3, and diff the probability column to see which races are moving.