435 seats in the House of Representatives, 35 Senate elections, and numerous additional state and local contests will be on the ballot. Yet control of Congress on November 3 is likely to be decided in only a handful of states and congressional districts. The 2026 midterm elections will be shaped by national issues, but their effects will appear very differently across the American electoral map. While a small group of states will determine the balance of power in the Senate, competition in the House of Representatives will be concentrated in just a few dozen congressional districts. At the same time, the country's political geography continues to evolve: formerly Democratic-leaning industrial regions are voting more Republican, growing suburban areas are in some cases becoming more Democratic, and Donald Trump's much-discussed gains among Hispanic and previously disengaged voters in 2024 have not proven equally durable everywhere. Anyone seeking to understand who will control Congress in the years ahead must therefore look not only at how America votes, but above all at where it votes.
