GREELEY, Colo. -- Republican Rep. Marilyn Musgrave lost her bid for a fourth term as Democrats surged across Colorado, picking up two congressional seats and delivering nine electoral votes to Barack Obama.

The Democratic tide in Colorado also appeared to include election of the nation's first openly gay non-incumbent, Jared Polis, in a left-leaning district with an open seat.

"So I guess I'm your next Congresswoman, " newly elected Betsy Markey told a proud crowd at the Marriott in Fort Collins.

In a brief and passionate acceptance speech delivered close to 11 p.m. Tuesday, Markey told supporters she plans to make health care reform a priority once she gets to Washington as the first Democrat to hold Colorado's 4th Congressional District seat in 36 years.

"You know, President Truman once said it's amazing what you can accomplish if you don't care who gets the credit. And there are so many people here tonight, all across the district, who worked so hard. This victory was hard earned and it belongs to all of you. Thank you so much," Markey said.

Musgrave, an ally of President George W. Bush, tried in recent months to distance herself from the unpopular president. But amid a national turn away from Bush, and Democratic gains in her sprawling northern and eastern Colorado district, Musgrave faced a hearty contest from Markey, a businesswoman.

With 90 percent of the projected vote counted, Markey lead Musgrave 55 percent to 45 percent.

The Markey-Musgrave 4th District battle eclipsed a slate of otherwise ho-hum House races.

Markey, owner of a technology business and first-time candidate, was cheered by supporters in a Greeley restaurant before polls closed. She said she was confident all along she could defeat the three-term incumbent in a district where Republicans still hold a narrow registration advantage, but not as much as even two years ago.

"I think we need to get the economy on track. We need to create new jobs, reduce the deficit," Markey said.

Musgrave, who typically eschews press coverage, had not appeared before supporters gathered in Greeley.

The Markey win gives Democrats a 7-2 advantage in Colorado's congressional delegation. Earlier in the evening, Democratic Rep. Mark Udall was declared the winner of an open Senate race.

Elsewhere around the state:

Democratic Rep. Diana DeGette cruised to re-election and becomes the state's senior member of Congress, representing since 1997 a district that includes all of Denver;

Democratic Rep. John Salazar led in his bid to return to Congress for a third time from the state's largest geographic district, which includes all of western Colorado;

Republican Rep. Doug Lamborn won re-election handily after surviving a vigorous primary battle in a conservative district that includes Colorado Springs; and

Democratic Rep. Ed Perlmutter earned a second term in a suburban Denver district.

In two open seats, the incumbent party held on with little challenge.

Polis, co-founder of the online greeting card company bluemountainarts.com, said he benefited from a Democratic surge, even though the 2nd District was already solidly Democratic.

Polis said his top priorities would be ending the war in Iraq and revisiting financial laws to try to prevent another financial collapse on Wall Street.

And in the 6th District, where Rep. Tom Tancredo is retiring, Republican secretary of state Mike Coffman defeated Hank Eng.

Coffman overcame a crowded pack of Republicans in the primary for one of the nation's wealthiest districts that includes suburbs south of Denver.