Top-Down Monte Carlo · 40,000 Simulations
House Senate Close Races Timeline Swing Lab

2026 Monte Carlo Election Simulator

Lower chamber · All 435 Districts

U.S. House of Representatives

Districts shaded by forecast rating. Click any district to inspect its projected vote share, polling average, fundraising, and election history.

Simulated Democratic seat distribution

All 435 House districts: win probability strip & race table

Upper chamber · 35 Seats on the Ballot

U.S. Senate

States with a 2026 Senate election shaded by forecast rating. Click any contested state for candidate matchups and live polling.

Simulated Democratic caucus seats

All 35 Senate races: win probability strip & race table

Key battlegrounds

Closest races deciding Congress

Seats rated Lean or Toss-up in either chamber, ordered by how close each race is to even odds. Click any row to inspect candidate matchups, polling averages, and historical margins.

Competitive Senate races

Competitive House races

Campaign trajectory

How the forecast has evolved

Interactive scenario sandbox

Election Night Roller & National Swing Lab

Draw a single correlated election night across all 435 House seats and 35 Senate races, or shift the national generic ballot to see how a wave scenario updates the chamber maps and seat counts above.

Interactive 2026 Election Night Roller & Swing Lab 40,000-Run Baseline
Showing the published 40,000-run baseline forecast across all 435 House districts and 35 Senate races. Click Roll 1 Simulated Election Night to draw a correlated national, state, and district election outcome on the maps above, or drag the National Environment slider to test a wave scenario.
Baseline (0.0 pts)
R+6 pts wave Published Baseline D+6 pts wave
Generated by pipelines/model.py and pipelines/report.py. Switch to the Interactive Swarm Atlas, read the Methodology & Historical Backtests, read the Blog Post, or ☕ Buy Me a Coffee.
Required Data Attributions: MIT Election Data + Science Lab (MEDSL, CC BY 4.0) · Voting and Election Science Team (VEST, CC BY 4.0) · Harvard Election Data Archive (HEDA, CC BY) · Cooperative Election Study (CES, CC BY 4.0) · Heideman (2026) Redistricting boundary archive (CC BY 4.0) · OpenElections Project (CC BY 4.0) · UF Election Lab Early Voting Tracker (CC BY 4.0) · FiveThirtyEight Pollster Ratings archive (CC BY 4.0) · Wikipedia Contributors (CC BY-SA 4.0). Full license & citation details →