Here are the key 2026 House and Senate races to watch that could decide control of Congress

With margins tight in both chambers, control of Congress in 2026 is expected to hinge on a small group of competitive Senate contests and House districts sensitive to national trends. As America plunges into a new year, here are the races that are most likely to define the midterm races.

Senate Republicans are looking to maintain their razor-thin majority after flipping the upper chamber in 2024. There are 33 seats in-cycle in the forthcoming midterms, which often act as a check on an incumbent president's performance.

What to watch: Before the general election, Republicans will first have to let the dust settle on a bloody, four-way primary fight among Reps. Buddy Carter, R-Ga., Mike Collins, R-Ga., former University of Tennessee head football coach Derek Dooley and horse trainer Reagan Box. Republicans' prized candidate, Georgia Gov. Brian Kemp, opted not to enter the contest, leaving a wide open playing field for the GOP to fight over. 

What to watch: Democrats believe they can flip the seat for the first time since 2008 and hope that former North Carolina Gov. Roy Cooper will carry them to victory and provide a crucial win to tip the balance of power. Republicans scored their preferred candidate, too, in former Republican National Committee Chair Michael Whatley. He will have a primary challenge though from Michele Morrow. 

Why it matters: Similar to North Carolina, Democrats lost their incumbent Sen. Gary Peters, D-Mich., to retirement. Both parties are now gunning for the open seat, but Democrats' have a tangled primary to survive first before their true candidate emerges. 

What to watch: Rep. Haley Stevens, D-Mich., state Sen. Mallory McMorrow and physician Abdul El-Sayed, are all in on the Democratic side, while Trump and Republicans have coalesced behind former Rep. Mike Rogers, who narrowly lost to Sen. Elissa Slotkin last year. 

Control of the House is likely to hinge on fewer than two dozen districts nationwide, as both parties focus their resources on a small set of competitive seats that could decide the chamber. The battlegrounds span suburbs, rural communities and diverse metro areas, underscoring how varied the path to a majority has become.

Why it matters: With a history of close results, Iowa's 1st District is once again a top battleground as Republican Rep. Mariannette Miller-Meeks seeks re-election.

Why it matters: Held by GOP Rep. Tom Kean Jr., New Jersey's 7th is a high-income, college-educated suburban district that has repeatedly swung with the national political climate and historically punished incumbents during unfavorable cycles.

What to watch: Whether suburban voters continue drifting away from Republicans or stabilize in a midterm environment. A shift here would offer an early read on how educated suburbs are responding to the party in power.

Why it matters: New York's 17th District, which previously backed former President Joe Biden, is represented by GOP Rep. Mike Lawler and is expected to play an outsized role in determining House control.

What to watch: Whether Democrats can effectively harness heavy national spending and messaging in a district expected to draw intense attention.

What to watch: Economic pressures and immigration debates are expected to shape how working-class and Latino voters approach the race.

Why it matters: California's 22nd, represented by GOP Rep. David Valadao, has remained a perennial battleground for more than a decade, shaped by its agricultural economy and a large Latino electorate sensitive to turnout swings.

What to watch: Whether Democrats can boost turnout enough to flip the seat, and whether Central Valley races help offset Republican gains elsewhere in the country.