Control of both chambers of Congress is up for grabs this fall. Democrats’ chances to seize power from the Republicans hinge on a narrow set of battleground seats and states.

There will be elections in every one of the 435 seats in the House of Representatives and 34 in the Senate in November. But only a small fraction are truly competitive. Here are the races expected to decide the midterm elections, according to the most recent ratings by the Cook Political Report.

House

35 competitive races

195 solidly
or likely Dem.

218 districts
for control

205 solidly
or likely Rep.

The magic number to win the majority in the House is 218 seats.

Right now, Democrats would need victories in 11 of the 18 races that Cook rates as tossups to clinch the majority, so long as they also secure seats leaning or likely Democratic. In order for Republicans to keep control, they need to win eight of the tossup races, plus the ones that lean in their favor.

The political environment favors Democrats. They have been winning in special elections — and won governors races last year — by wide margins. President Trump is increasingly unpopular as gas prices remain high and the Iran war drags on.

But the 2026 congressional map has been remade through the nationwide redistricting wars to favor the G.O.P. And the maps remain in flux as some Republican states, especially in the South, are pushing to erase even more Democratic districts.

The most competitive House races

All Tossups (18)Lean Dem. Lean Democratic (12)Lean Rep. Lean Republican (5)

DistrictIncumbentRating ▾Ariz. 1NoneTossupPolls ›Ariz. 6Juan Ciscomani Ciscomani RTossupPolls ›Calif. 22David Valadao Valadao RTossupPolls ›Colo. 8Gabe Evans Evans RTossupPolls ›Fla. 25Jared Moskowitz Moskowitz DTossupIowa 1Mariannette Miller-Meeks Miller-Meeks RTossupIowa 3Zach Nunn Nunn RTossupMich. 7Tom Barrett Barrett RTossupPolls ›N.J. 7Thomas Kean Jr. Kean RTossupPolls ›N.Y. 17Mike Lawler Lawler RTossupPolls ›

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Note: “None” indicates races where the current representative announced retirement or the incumbent lost their primary.

The House battleground is likely to change several times between now and November. Some House races that are less competitive now may become so this fall. And some races currently seen as competitive seats are likely to fall off the map entirely, as incumbents or challengers fade.

Senate

10 competitive races

2 lean R Rep. 2 likely R Rep.

10 solidly
or likely Dem.
and 34 not up
for re-election

50 seats
for control

15 solidly Rep.
and 31 not up
for re-election

Republicans currently hold 53 Senate seats. Democrats would need to flip four states, while defending their two most vulnerable seats in Michigan and Georgia, in order to win the majority.

Democrats would need to win 51 seats because in a 50-50 Senate, Vice President JD Vance would cast the tie-breaking vote for Republicans. It’s a tall task that would require Democrats to win seven of the eight races that Cook rates as tossups or leans, including at least two seats in states that Mr. Trump won by double digits in 2024 — between Alaska, Ohio and Texas.

The most competitive Senate races

All Tossups (3)Lean Dem. Lean Democratic (3)Lean Rep. Lean Republican (2)

Note: “None” indicates if a current senator announced retirement or the incumbent lost their primary.

The odds are one reason Democrats have pushed to compete for seats in states like Texas, Iowa and Nebraska, even though these races more strongly favor Republicans. In fact, in Nebraska, the party has rallied behind an independent candidate, Dan Osborn, as the best shot to unseat a Republican.