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Each of the nation's 20 wealthiest congressional districts, when measured by median household income, will be held by Democrats in the upcoming Congress.

Republicans did not win one.

These districts are not broadly dispersed. Only one is not on the East or West Coast.

Seven are in or near New York City. Five are in the San Francisco Bay Area. Four are in suburbs of Washington, D.C. Two are in Southern California. One is near Boston. And another -- the only one in the middle of the continent -- sits west of Chicago.

In the 115th Congress, which is about to expire, Republicans held four of these districts. In November's midterm, they lost them all.

California's 18th, held by Democratic Rep. Anna Eshoo, is the richest in the country, according to estimates published by the Census Bureau in its Table S1903. It has a median household income of $122,124, which is more than twice the national median household income of $57,652.

It sits south of the San Francisco and includes part of the Santa Clara Valley.

"The 18th District is the birthplace of Silicon Valley, world center of the information technology and biotechnology industries," says Eshoo's official congressional website.

"The electronics and technology industries continue to flourish," says her site, "and leaders such as LinkedIn, Netflix, HP, Google, Symantec, Intuit, VMWare and a host of other leading firms are headquartered in the 18th District."

Another part of Silicon Valley makes up the third wealthiest district, California's 17th. It is held by Democrat Rep. Ro Khanna and has a median household income of $115,390.

Like Eshoo, Khanna boasts on his website that he represents Silicon Valley. "I am proud to represent the 17th Congressional District of California, which encompasses cities in Santa Clara and Alameda counties that together are known as Silicon Valley," he says.

The second-wealthiest congressional district -- richer than Khanna's Silicon Valley district but poorer than Eshoo's -- is Virginia's 10th. It stretches through the western suburbs of Washington, D.C., to the West Virginia line. The median income here is $119,874.

In the expiring Congress, this district was held by Republican Rep. Barbara Comstock. She lost the midterm to Democrat state Sen. Jennifer Wexton.

In this district, as Comstock notes on her website, high-tech meets the federal government. "The 10th District," says Comstock's site, "has attracted many of the leading internet, high-tech, health, and defense companies in the world to Northern Virginia and the Shenandoah Valley and is home to thousands of federal employees and other highly skilled professionals and entrepreneurs."

The other three suburban D.C. congressional districts that rank among the nation's 20 wealthiest are Virginia's 11th, held by Democratic Rep. Gerald Connolly, which ranks No. 6 with a median income of $107,567; Virginia's 8th, held by Democratic Rep. Don Beyer, which ranks No. 8 with a median income of $103,414; and Maryland's 8th, held by Democratic Rep. Jamie Raskin, which ranks No. 13 with a median income of $100,728.

In addition to Eshoo's and Khanna's Silicon Valley districts, the other three Bay Area districts that rank in the top 20 are California's 15th, held by Democratic Rep. Eric Swalwell, which ranks No. 10 with a median income of $103,109; California's 14th, held by Democratic Rep. Jackie Speier, which ranks No. 11 with a median income of $101,753; and California's 12th, held by House Democratic leader Nancy Pelosi, which ranks No. 17 with a median income of $97,282.

Swalwell's district sits in the East Bay, and Speier's sits on the northern San Francisco Peninsula and southwest corner of the city.

Pelosi's district, of course, covers most of San Francisco itself.

The fourth-wealthiest district is New Jersey's 7th, where the median income is $109,061. It is west of New York City and was represented in the expiring Congress by Republican Rep. Leonard Lance. He lost the midterm to Democrat Tom Malinowski.

The other six New York area districts among the nation's 20 wealthiest include New York's 3rd, held by Democratic Rep. Thomas Suozzi, which ranks No. 5 with a median income of $108,136; New Jersey's 11th, won in an open-seat midterm election by Democrat Mikie Sherrill, which ranks No. 7 with a median income of $107,027; New York's 12th, held by Democratic Rep. Carolyn Maloney, which ranks No.12 with a median income of $100,828; New York's 4th, held by Democratic Rep. Kathleen Rice, which ranks No. 14 with a median income of $100,387; New Jersey's 5th, held by Democratic Rep. Josh Gottheimer, which ranks No. 15 with a median income of $98,863; and New York's 17th, held by Democratic Rep. Nita Lowey, which ranks No. 19 with a median income $95,454.

Back out on the West Coast, in Los Angeles County, California's 33rd, held by Democratic Rep. Ted Lieu, ranks No. 9 with a median income of $103,176. In Orange County, California's 45th ranks No. 16 with a median income of $97,431. In that district, incumbent Republican Rep. Mimi Walters lost the midterm to Democrat Katie Porter.

The geographical outliers -- not in the San Francisco, Los Angeles, New York or Washington areas -- were Illinois' 6th, which ranks No. 18 with a median income of $96,460; and Massachusetts' 4th, which ranks No. 20 with a median income of $95,353.

In Illinois' 6th, Democrat Sean Casten beat Republican incumbent Rep. Peter Roskam in the midterm.

In Massachusetts' 4th, Rep. Joseph P. Kennedy III ran for re-election unopposed.