Clusters of wealthy, educated suburban voters shifted their loyalties to Democratic candidates on Tuesday, turning on Republicans and allowing Democrats to regain control of the House.

A USA TODAY analysis of midterm election returns across the nation found more than 80 suburban counties and cities – with high incomes and a large number of college-educated voters – voted more Democratic compared to 2016.

The majority of the areas showed single-digit-percentage-point increases for Democrats, but more than 20 witnessed a double-digit swing, sometimes turning red counties blue. Cobb County outside Atlanta, for instance, saw 53 percent of their voters go for Democrats, up from 39 percent in 2016.

The left turn proved vital, knocking off Republican incumbents in suburban districts and seemingly blurring the boundary of Trump country. Analysts and Congressional leaders all but reclaimed the suburbs for Democrats following the election.

"We're delighted that suburbia, which used to be so Republican, is now Democratic," Senate Minority Leader Chuck Schumer, D-N.Y., said Wednesday. He warned the suburban retreat, along with turnouts from women and minorities, should worry Republicans and President Donald Trump in the 2020 election.

"Just as the rural vote revolt has continued to benefit Trump and Republicans, a new suburban revolt, especially among college-educated women, has worked to the benefit of the Democratic party and will probably continue," said Larry Sabato, founder and director of the University of Virginia Center for Politics.

Take Republican-leaning Delaware County, Ohio, north of Columbus. A quarter of its votes went for Democrats in 2016, when Trump narrowly won the state. On Tuesday, that number jumped to 44 percent – a fluctuation of 19 percentage points. Morris County, New Jersey, sitting across the Hudson River from New York City, posted a 15-percentage-point increase for Democrats. DuPage County outside Chicago saw a 10 point change.

The trend persisted in suburbs across the country and in congressional districts that flipped from Republican to Democrat, contributing to the Democrats' new House majority.

Jennifer Wexton, who upset Republican incumbent Rep. Barbara Comstock, received a boost by 10-point gains in Fairfax and Loudoun, two suburban Virginia counties outside Washington, D.C. In Kansas, Sharice Davids defeated Republican Rep. Kevin Yoder with the help of a 14-point swing in suburban Johnson County outside Kansas City. Former Navy helicopter pilot Mikie Sherrill defeated Republican challenger Jay Webber due to the shift in Morris County, New Jersey.

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USA TODAY analyzed America's wealthiest and most-educated counties and cities with competitive House races, together representing 36 million people. Some county numbers weren't yet available. In each of these counties or cities, at least 30 percent of the population has a college degree. In many cases, it's more than half. The areas have median household incomes of at least $62,000 or more, but often topping $100,000.

Of the 123 counties and cities, including the more than 80 in the suburbs, Democrats gained ground in all but three, where they held even. They won outright in 60 of these areas, up from 39 in 2016.

Political analysts see the trend as evidence that pragmatic suburban voters can't be typecast. Or, perhaps, they've grown weary of Trump's controversial comments and positions.

"They're put off by the harsh rhetoric of Trump on almost everything," Sabato explained. "I have seen not only no softening toward Trump among the highly educated, I have seen an intensification of the anger, resentment and opposition to him."

The midterms exemplified how malleable suburban voters can be, said Sam Abrams, a scholar at the American Enterprise Institute who writes about political geography.

Over the past two decades, while rural areas became more Republican and urban centers became more Democratic, the suburbs waffled. The bloc moved slightly to the left or right depending on the election, Abrams said.

"These folks are flippable, and that's what we saw here," he said. "They're going to be retrospective voters. They're going to look at what what's going on and they're going to say, 'Are we happy with it? Are we comfortable with it?' "

Making that group comfortable, both Sabato and Abrams say, should be a goal of both parties in 2020.

"The only competitive territory is the suburbs and the exurbs," Sabato said.

Contributing: Brad Heath

Follow Sean Rossman on Twitter: @SeanRossman