Representative Abigail Spanberger, a prominent Virginia Democrat who was repeatedly able to win in a conservative-leaning district, announced on Monday that she would run for governor in 2025, leaving open a competitive seat that could be crucial to her party’s efforts to win back control of the House next year.
Ms. Spanberger, 44, is seen as among the strongest Democratic contenders to succeed Gov. Glenn Youngkin, a Republican who is term-limited. Her decision not to seek re-election to Congress leaves House Democrats scrambling to hold a seat that is regularly in play for both parties.
“Virginia is where I grew up, where I am raising my own family and where I intend to build a stronger future for the next generation of Virginians,” Ms. Spanberger said in a statement.
Ms. Spanberger is the first candidate to announce a run for Virginia governor. Her early announcement is intended to allow a successor to build a campaign for the 2024 House race, which Democrats believe would provide a more favorable electorate than a special election.
But House Republicans said their odds of claiming the seat improved substantially with Ms. Spanberger’s planned exit, pointing to it as the latest example of a Democrat in a competitive seat choosing to run for higher office rather than remain in the House.
Other examples include Representatives Elissa Slotkin of Michigan and Katie Porter of California, both of whom are pursuing Senate seats.
“Swing district House Democrats are scrambling for the exits and creating @NRCC pickup opportunities from coast to coast,” Jack Pandol, a spokesman for the National Republican Congressional Committee, wrote on X, formerly known as Twitter. “We are in prime position to pick up this seat.”
Ms. Spanberger, a former C.I.A. officer, won election in 2018 as part of a wave of centrist women — many of them with national security experience — who said they were running to counter President Donald J. Trump and whose victories propelled Democrats to the House majority. She developed a reputation in Congress as a Democrat willing to buck her party, refusing to vote for Representative Nancy Pelosi of California to be speaker and pushing to bar members of Congress from trading stocks.
Even so, Ms. Spanberger was recently elected as a member of Democratic leadership to represent the interests of members from battleground districts.
Ms. Spanberger currently holds the central and Northern Virginia seat formerly occupied by Representative Eric Cantor, a Republican and former House majority leader. He was defeated in a primary in 2014 by a Tea Party-aligned Republican, Dave Brat, who then lost to Ms. Spanberger in 2018.
She won two close re-election campaigns, though the seat was redrawn ahead of the 2022 race, making it slightly more favorable to Democrats.