With an estimated 99% of ballots tallied, Laubacher held a 3,525-vote lead out of just under 385,000 votes counted, a margin of 0.91%. She secured 48.8% to Boebert's 47.89%, while Libertarian Douglas Mangeris trailed with 3.31%.

Laubacher, a retired U.S. Navy rear admiral and former National Security Council official, claimed victory Monday after CNN projected her win, but Boebert insisted it was too early to declare the race finished while thousands of ballots remained outstanding. On Friday, Boebert's campaign attorney, former Republican Secretary of State Scott Gessler, called it "irresponsible" to declare a winner before all ballots were counted.

"I'm honored by the trust the people of Colorado's 4th District have placed in me," Laubacher said in a statement. "This campaign was never about party labels. It was about putting people first."

She continued: "This victory is historic. But making history means nothing if we don't make a difference. My focus is simple: lower costs, protect healthcare, strengthen rural communities, take on corruption in both parties, and hold Washington accountable."

Laubacher attended orientation for new House members in Washington this week, where she reportedly received sustained applause from fellow Democrats for ousting the incumbent in one of the reddest districts to flip in this year's midterms. Two years ago, President Donald Trump carried the district's electorate by an 18-point margin.

Boebert, in an online video Monday, said her opponent and others had wanted to "prematurely declare victory" before the deadline to finish counting. "Declaring victory now is like icing a cake before it comes out of the oven," she said, adding that she was grateful to voters and her campaign team. "Regardless of the final outcome, we will move forward to future victories together. We'll make sure that every eligible vote is counted and every single voice is heard before we take any next steps."

In a fundraising email the same day, Boebert said: "Our legal team expects a recount will happen one way or another, and we're preparing for it NOW." However, Laubacher's lead is too wide to trigger an automatic recount under state law, which requires a margin of 0.5% or less of the highest vote-getter's total. That would mean a difference of under 1,000 votes—less than one-third of Laubacher's winning margin. Either candidate or a political organization can request a recount regardless of margin, but they must pay for it. Boebert told reporters in Washington earlier in the week that she didn't expect to pay for one, and before the race was called, she said that if she lost, she didn't plan to seek a rematch.

County clerks had until just before midnight Thursday to receive cured and military and overseas ballots. Election officials also withheld an unspecified number of ballots to include in the final count to preserve ballot anonymity—so voters' choices wouldn't be apparent in counties where only a handful of late-arriving ballots would be added to the totals.

Laubacher led Boebert since election night, but her margin narrowed in the days since as county election officials continued to update results. After closing to a roughly 3,000-vote advantage late last week, Laubacher maintained and even grew her margin as returns trickled in. On Friday, clerks posted the remaining vote totals, including cured and overseas ballots that had to be received by 11:59 p.m. Thursday. Voters can cure ballots by fixing signature or other discrepancies, while military and overseas ballots must be postmarked by 7 p.m. Nov. 3 to be counted.

Boebert's loss means Colorado will send seven Democrats and just one Republican to the U.S. House next year, following a massive blue wave in this year's midterms that swept Republicans from office across the country and saw Democrats win control of both chambers of Congress. In Colorado, Democrats unseated three incumbent Republican House members. In addition to Boebert, U.S. Rep. Gabe Evans fell to Manny Rutinel by nearly 15 points in the 8th Congressional District, and Jessica Killin defeated U.S. Rep. Jeff Crank by an almost 5-point margin in the 5th Congressional District, which had never before elected a Democrat. The lone Republican left standing is U.S. Rep. Jeff Hurd, who fended off Democrat Dwayne Romero by nearly 2 points in the 3rd Congressional District.

When lawmakers are sworn in next year, Democrats stand to hold the largest majority in Colorado's congressional delegation since 1940, when Democrats held all four House seats and both Senate seats. Both of the state's U.S. senators are Democrats—Michael Bennet, serving his third full term, and John Hickenlooper, who was elected to a second term by a wide margin on Nov. 3.

Laubacher's win ends the congressional tenure of the state's senior and most prominent Republican, marked by Boebert's unconventional approach and high-profile clashes with Democrats and members of her own party, including Trump. The 58-year-old Laubacher, a first-time candidate, said she ran to bring more mature representation to the district, including finding common ground on affordability, healthcare and housing. She moved into the district last summer from the nearby Ken Caryl neighborhood and now lives in Highlands Ranch.

Boebert, 39, burst onto the political scene in late 2019 when she confronted then-presidential candidate Beto O'Rourke over his proposal to confiscate firearms. "Hell no, you won't take away our guns!" she told O'Rourke at a campaign stop in Aurora, garnering national headlines. A few months later, she launched a primary challenge against five-term U.S. Rep. Scott Tipton. The owner of Shooters Grill, a gun-themed restaurant in Rifle, Boebert vowed to take a more aggressive stance against "all the left-wing lunatics" than the more moderate incumbent had. She surprised Tipton in the 2020 primary, becoming the first Colorado candidate to unseat an incumbent House member in a primary in 48 years, and went on to win election with Trump's endorsement.

Two years later, Boebert came within 546 votes of losing the seat to Democrat Adam Frisch. Nearly a year before the 2024 election—with Frisch seeking a rematch while posting record fundraising hauls and Boebert's own internal polls showing she was vulnerable—Boebert moved across the state to run for another term in the more solidly Republican 4th Congressional District after the seat's GOP incumbent announced he wouldn't seek another term. Her move in late 2023 came on the heels of a major controversy after she and a male companion were ejected from a Denver performance of the musical "Beetlejuice" for inappropriate behavior. She survived a crowded primary in the new district and beat Democratic nominee Trisha Calvarese by an 11-point margin. Her campaigns have focused on supporting Trump, border security, boosting fossil fuel production and reducing government spending and federal regulation.

Anchored by Douglas County, the 4th District covers all or parts of 21 counties, including Colorado's Eastern Plains and the Loveland area. Republicans who held the seat before Boebert routinely won with margins topping 20 percentage points. According to vote totals posted by the Colorado Secretary of State's Office, Laubacher carried the district's more densely populated portions in Douglas, Larimer and Arapahoe counties, while Boebert led in smaller, rural counties. The district's voters have elected a Democrat only once in the modern era, in 2008, when the district included nearly all of Larimer and Weld counties and extended into Fort Collins and Greeley, making it more competitive than it has been since subsequent redistricting.

In the week before the election, national forecasters moved the district into the "leans Republican" category—one step away from a "toss-up"—suggesting the race was more up for grabs than the district's makeup and electoral history implied. Hours before Laubacher claimed victory, Attorney General Phil Weiser, Colorado's Democratic governor-elect, applauded a CNN story projecting that Boebert had lost. "This is what democracy looks like!" Weiser said on X, adding that Laubacher "is the real deal, worked hard to earn the trust of the people of the 4th Congressional District, and will be an outstanding member of Congress."