Voters in Denver’s suburbs just did something that doesn’t happen very often in Colorado in an election – unseat a congressional incumbent.

Members of either major party have only managed to pull it off three times in the last 30 years, but Democratic attorney Jason Crow ended Republican U.S. Rep. Mike Coffman’s three decades in elected office by winning the 6th Congressional District.

In every other Colorado congressional district, the House seat stayed in the hands of the incumbent or with the party that now holds it in the election that ended Tuesday.

“574 days ago in the early morning hours, I filed my paperwork as a candidate … Tonight I am humbled to stand before you as the congressman-elect for this district,” Crow told hundreds of his supporters at 8:27 p.m. at his election-night gathering at the DoubleTree by Hilton Hotel Denver Tech Center in Greenwood Village.

Crow acknowledged that his run was “a bold idea for someone who had never run for office before.”

He added: “Tonight you sent a message that democracy is alive and well in America and that you will not be silent.”

The race was decided quickly, with news outlets declaring Crow the winner within 90 minutes of the polls closing. Final unofficial results showed Crow winning by nearly 9 percentage points.

Crow thanked his opponent for a “spirited and hard-fought campaign.”

“Mike Coffman and his supporters are not our enemies,” he said “… This is politics, not war. I will never stop finding common ground where I can. I wish him the very best.”

The race was long seen as a harbinger for whether the Republicans could keep control the U.S. House of Representatives or Democrats could flip the 23 seats they needed to take the gavel.

As it turned out, Democrats won the House with the help of wins like Crow’s.

Coffman has represented the nearly evenly divided 6th Congressional District – it covers portions or Adams, Arapahoe and Douglas counties on the east side of the Denver metro area – for five terms, winning re-election even as Democrats Barack Obama and Hillary Clinton carried the seat.

But President Donald Trump’s unfavorable ratings in the suburban district – driving what looks to be an unusually high Democratic turnout for a midterm election – did not help Coffman, even though he had pitched himself as the rare Republican willing to “stand up” to the president on crucial issues like immigration.

Crow and his free-spending allies nevertheless tried to tie the incumbent to Trump – by a measure that Coffman disputes, that the Republican has voted with the president more than any other member of Congress from Colorado – and pointing out that Coffman has received the most campaign cash in the delegation from the National Rifle Association.

Coffman, at a Republican gathering in Lone Tree, said he tried to focus on local issues, but it turned into a referendum on Trump, and that was a fight he said he couldn’t win.

“My only hope of winning was to localize the race, a referendum on my leadership, and if the race was nationalized as a referendum on the president, … I simply could not win,” he said.

Coffman spoke of his honor in serving immigrant communities in his district, convincing them that just because Republicans are anti-illegal immigration they are not anti-immigrant.

“The American Dream has not only made me a better congressmen, it’s made me a better person,” Coffman said.

Coffman’s supporters had warned against counting the Republican out, noting that he had confounded prognosticators and survived blue waves before.

> RELATED: Colorado US Rep. Coffman is fighting for his political life

Coffman has deep ties to the district’s many immigrant communities – 20 percent of its residents were born in another country – and constituent service like helping an Aurora family save their adopted toddler from deportation, as a recent Coffman ad reminds voters.

By the numbers, however, it was Crow’s race to lose.

National GOP groups abandoned the race in recent weeks, announcing they were canceling millions of dollars worth of TV ads as polls found Crow leading by between 9 and 11 percentage points. What’s more, Crow had raised $5 million to Coffman’s $3.4 million, and outside liberal groups were out-spending Coffman’s allies by a wide margin even before his main backers pulled out.

Early vote data through the morning before the election showed a Democratic advantage in the district, with Republicans lagging their rate of ballot return at the same point in the last midterm election, while Democrats were turning in ballots at a markedly higher rate than they did in 2014.

> RELATED: Tipton leads Mitsch Bush in Colorado’s 3rd CD, bipartisan poll shows

Early on, only other one of Colorado’s six other congressional districts looked to be up for grabs on Election Day – the sprawling 3rd Congressional District, where Democrat Diane Mitsch Bush was challenging four-term Republican U.S. Rep. Scott Tipton.

But Tipton wound up defeating Mitsch Bush by a nearly 9-point margin.

The battle for the 3rd hadn’t drawn the kind of attention or spending that the Coffman-Crow race has, but some polling and a handful of election forecasters pegged it as the other one to watch in Colorado.

Tipton’s campaign had portrayed Mitsch Bush, a former state representative and county commissioner, as a radical leftist, a claim the Democrat rejects.

Instead, Mitsch Bush pointed to a bipartisan legislative record and awards from progressive and conservative groups.

National election blog FiveThirtyEight ranked the race a toss-up in October but shifted it back toward Tipton after a poll showed him with a 15-point lead.

A poll released Saturday by Republican firm JMC Analytics and Polling and Democratic firm Bold Blue Campaigns showed Tipton with a 5-point lead.

Although the Cook Political Report, listed the seat as a toss-up, it would have taken a nearly unprecedented Democratic turnout to dislodge Tipton.

Elsewhere in the state, Democrat Joe Neguse, a former University of Colorado regent, won the Boulder and Larimer county-centered 2nd Congressional District seat currently held by Jared Polis, the Democratic nominee for governor.

Neguse, an attorney and son of Eritrean refugees, is poised to become the first African-American memer of Congress from Colorado. He faced a challenge from Republican newcomer Peter Yu, Libertarian Roger Barris and independent Nick Thomas.

The other seats are represented by incumbents who were all re-elected: