There are 435 members of the House of Representatives up for re-election this year, but how many of those races will actually be competitive — and how many will see an influx of money in an effort to influence the outcome?

Sunlight took an early look at competitive House races to find out. We used analysis from the Rothenberg & Gonzales Political Report to determine battleground races. Of the all House elections that will occur this year, Rothenberg rates 32 races to be “toss-up” or leaning slightly toward one party or another — seven currently held by Democrats and 25 currently held by Republicans. In addition to battleground races, we also reached out to reporters on the ground in those districts to see what they’re seeing in those races.

This analysis excludes some races that include House leadership, like Rep. Paul Ryan, R-Wis., or Rep. Nancy Pelosi, D-Calif., who raise and spend boatloads of cash for their party, but often very little on their own races. The analysis only includes spending from candidate committees, PACs and super PACs; dark money spending is not included. We paired our analysis of Federal Election Commission data with some outside expertise, interviewing reporters from the Arizona Republic, Baltimore Sun, National Journal, MinnPost and Texas Tribune on the top-spending competitive House races so far in 2016.

1. Maryland 8th District: $16.1 million

The Maryland primary is April 26, and according to John Fritze, Washington correspondent for The Baltimore Sun, the Maryland 8th District is seeing a heavily contested Democratic primary to replace Rep. Chris Van Hollen, who is running for Senate. The race is the most expensive House race in the country so far.

Businessman David Trone is driving the spending in the race, according to Fritze. “He is self-funded and spending [more than] $9 million of his own money.” A recent report by NPR blared the headline “This candidate is spending more than anyone ever for a seat in Congress.”

But that isn’t the only reason we are seeing a lot of money in this race, Fritze said. “Bethesda, Chevy Chase and Potomac are all wealthy neighborhoods. Even without Trone’s money you would see this as a top-spending House district.”

Kathleen Matthews, a former Marriott executive and broadcast journalist competing for the seat, is also “raising a ton of money,” $2.1 million to be exact, for her campaign. Additionally, Women Vote!, the super PAC arm of EMILY’S List, spent more than $291,000 supporting Matthews. Other candidates in the crowded primary include Will Jawando, a former Obama aide and state house candidate, state Sen. Jamie Raskin and state Delegate Kumar Barve.

2. Ohio 8th District: $9.9 million

Don’t let the total spending for this race fool you: $6 million out of the nearly $10 million spent has been from retiring Republican Rep. John Boehner’s campaign, which did not spend, as far as we can tell, directly on the race. With that said, the spending for the March 15 special election primary did result in $3.8 million in spending from candidates and outside PACs.

Businessman Warren Davidson was both the winner of the very crowded GOP primary and the top spender, doling out $709,000. Outside PACs dwarfed that, however, spending a total of $1.8 million. Club for Growth’s super PAC and PAC poured $1.2 million into the district to support Davidson. Other groups to get involved in the race include the super PAC Defending Main Street, which spent $280,000 opposing Davidson, and the Credit Union National Association PAC spent $250,000 to support candidate Timothy Derickson.

3. Illinois 10th District: $4.4 million

Kimberly Railey, who covers House campaigns for National Journal, said in an email that this race has been contested for several cycles in row. “Democrats are determined to take back this swing seat from Republican Rep. Robert Dold, who will face former Rep. Brad Schneider for the third time in November.” You read that right, this is the third time Schneider will face Dold in an election to represent the district.

Railey says the Democratic primary was much more competitive than many predicted. A challenge from Mayor Nancy Rotering of Highland Park, a Chicago suburb, led to more than $1.5 million being dumped into the race.

Get ready for an expensive general election. According to Railey, Dold has the money edge: “As of March 31, Dold boasted a sizable cash edge over Schneider — $1.9 million to Schneider’s $547,000 — but that advantage will matter far less in coming months.”

Railey expects even more players insert themselves into the race “as the National Republican Congressional Committee, the Democratic Congressional Campaign Committee, and various outside groups turn their focus — and money — to the seat.”

4. Illinois 15th District: $3.7 million

In the safe Republican Incumbent Republican Rep. John Shimkus recently beat back a primary challenge from state Sen. Kyle McCarter in a costly bid. According to Railey, “[McCarter] drew outside help from the Club for Growth’s super PAC, which ran a TV ad slamming Shimkus as ‘one of the most liberal Republicans.’”

But Club for Growth wasn’t the only outside group to get involved. “The American Action Network fired back with a positive spot for Shimkus, who heavily outspent McCarter $793,000 to $191,000 from Jan. 1 to Feb. 24,” Railey said.

Don’t expect this race to stay on this list, though. Railey says, “Shimkus will have no trouble winning the general election in his safe GOP district.” No Democratic challengers has filed a fundraising report with the FEC.

5. Texas 8th District: $3.2 million

The Texas 8th is home to Republican Rep. Kevin Brady, who has served in Congress for 19 years and survived a challenge from conservative former state Rep. Steve Toth. The Texas Patriots PAC dropped $25,000 in online ads against Brady, while Will Tucker of the Center for Responsive Politics says Brady “was the main beneficiary of about $260,000 in outside spending in a primary that gave the House Ways & Means Committee chairman a scare.” This included more than $175,000 from the Congressional Leadership Fund, whose donors include Chevron, which recently made a $1 million contribution to the GOP-aligned super PAC.

6. Minnesota 2nd District: $2.9 million

Sam Brodey of the MinnPost says there is a lot more to come in the race to fulfill the seat left open by retiring GOP Rep. John Kline. On the Democratic side, Brodey says there is a clear frontrunner: “Angie Craig has a significant fundraising advantage over everyone at this point.” Craig also has “the capacity to self-fund to a meaningful degree, and has long had the enthusiastic backing of outside Dem groups going all-out to turn this seat blue, like EMILY’s List and the DCCC.”

Things aren’t as clear on the GOP side. “Establishment types, including retiring Rep. John Kline, himself a very good fundraiser, consider businesswoman Darlene Miller their best hope to hold the seat,” Brodey said.

If Miller wins the GOP primary, Brodey thinks “outside money from the usual suspects should flow freely. If a more strident conservative — either tea party activist David Gerson or radio host Jason Lewis — is the nominee, many expect that GOP pocketbooks will tighten, and perhaps export cash to a more winnable race.”

7. Indiana 9th District: $2.9 million

The safe Republican district is being vacated by Rep. Todd Young, who is running for Senate, and now the 9th District is seeing an open and hotly contested primary. Businessman Trey Hollingsworth is the big spender in the race, and, according to previous reporting by Sunlight’s own Libby Watson, he “has made large contributions to his own campaign.”

Other candidates include Attorney General Greg Zoeller and state Sens. Erin Houchin and Brent Waltz, whose campaigns have spent $221,000 and $258,000, respectively. This pales in comparison to the $1.3 million spent by Hollingsworth.

The spending in this race is almost all driven by pro-Hollingsworth forces, which account for a whopping 88 percent of total spending in the race. Hollingsworth’s outsider candidacy is facing some scrutiny as well: A recent article in The Indianapolis Star ran with the headline, “Trey Hollingsworth for Congress — rich carpetbagger or breath of fresh air?”

A fun fact about this race: A super PAC supporting Hollingsworth, which is primarily funded by his father, inexplicably put Sunlight’s phone number on an ad buy. The group has spent the most of any outside group in the race, doling out $487,000 in support of Hollingsworth. Additionally, a super PAC called Frugal Hoosiers has spent $171,000 on radio ads opposing Hollingsworth. Frugal Hoosiers has not filed a report with the FEC, so we are not sure who is funding the anti-Hollingsworth ads.

8. Maryland 6th District: $2.8 million

Fritze of The Baltimore Sun tells us that current Democratic Rep. John Delaney has done some interesting things so far in the race, including ads opposing Donald Trump aimed at GOP Gov. Larry Hogan. “Delaney is a wealthy, self-funder, who also does a really good job raising money,” Fritze says.

On the Republican side, the candidates to watch are Amie Hoeber, the frontrunner, and possibly David Vogt, who has been endorsed by the NRA. Hoeber has her own help, a super PAC, Maryland USA. According to Sunlight’s Real-Time Campaign Finance tracker, Hoeber’s husband, Mark Epstein has donated $2.1 million to Maryland USA that has already spent $1.6 million mostly on advertising and direct mail to boost her chances.

Fun fact: Fritze says “Delaney actually lives in the 8th district and not in the 6th.”

9. Arizona 2nd District: $2.6 million

Rebekah Sanders, congressional reporter for The Arizona Republic, says the Tucson area district was one of the closest races in the country in 2014.

McSally’s “$4 million haul dwarfs almost every other candidate in the country, but she’s spending a lot too,” said Sanders. McSally’s $2.3 million in spending has made up 88 percent of election spending in the district so far. And Sanders estimates that the bulk of that spending has gone toward direct mail fundraising.

Democrats Matt Heinz and Victoria Steele haven’t gained traction yet, and unless something changes, Sanders says, “It’s hard to see how the Democratic Congressional Campaign Committee or outside groups invest very much to flip the 2nd District.”

In terms of outside groups, this district has a hometown player: Sanders says former Rep. Gabby Gifford’s group, Americans for Responsible Solutions, which advocates for solutions to end gun violence, could get involved. “It was the top-spending group besides the parties,” says Sanders. “But the candidate at the time was Ron Barber, a Giffords aide who replaced her in Congress after they were both injured in a mass shooting. Without the same close ties, it’s unclear if ARS will support Heinz and Steele.”

And in terms of outside groups supporting McSally, Sanders thinks they “may not play heavily if McSally looks secure. But if Trump spells trouble, you can be sure GOP leaders will swoop in to try to rescue one of their most promising freshmen.”

10. Texas 15th District: $2.5 million

A contested Democratic primary drove spending to replace retiring Rep. Ruben Hinojosa in the district that spans from San Antonio to Nuevo Laredo. As far as we can tell, outside groups have steered clear of this race. The primary was very crowded — five candidates ran — and has now led to a May 24 runoff between Vicente Gonzalez, a lawyer and newcomer to politics, and Juan Palacios Jr., a former member of the Edinburg, Texas, school board. Gonzalez is the big spender in the race and has dropped $1.4 million so far, which is 56 percent of the total spending in the race, compared to Palacios who has only spent $262,000.

11. Maryland 4th District: $2.5 million (honorable mention)

A safely Democratic district, The Baltimore Sun’s Fritze again sets the scene for the Maryland 4th District, where current Rep. Donna Edwards is leaving to run for Senate. There are three big players in the competitive April 26 Democratic primary; state Delegate Joseline Pena-Melnyk, former gubernatorial candidate Anthony Brown and Prince George’s County State’s Attorney Glenn Ivey.

“Brown has been lackluster as a fundraiser and has loaned himself $500,000, and has spent most of that, which is not good considering he also has a loan left over from his [failed] gubernatorial run.”

Fritze says Pena-Melnyk has a lot of endorsements, including EMILY’s List and the Latino Victory Fund. “Even she is loses, she could potentially run for another office beyond her current state delegate seat.”

12. Texas 19th District: $2.4 million (honorable mention)

Republican Rep. Randy Neugebauer has held this seat since 2003, but is now retiring. Abby Livingston of The Texas Tribune said in a February report that the voters in the west Texas district that centers around the towns of Lubbock and Abilene have a lot of choices.

According to Livingston, former Texas Tech Vice-Chancellor Jodey Arrington, retired Air Force Colonel Michael Bob Starr, Lubbock Mayor Glen Robertson and five other candidates all sought the congressional seat. No one candidate cleared the necessary threshold to win the March 1 primary outright, so now Robertson and Arrington will face off on May 24.

In terms of cash on hand, both candidates are running even; Robertson’s at $291,000 and Arrington’s at $237,000. However, Robertson has shown the ability to raise much more money, to this point raising a total of $1.4 million compared to $656,000 for Arrington. Robertson’s fundraising prowess is the key reason this district has such high spending, as his campaign’s expenditures have made up 58 percent of all spending so far in the election.

Currently no big outside groups have stepped in, but a super PAC, Conservative Texans, has spent $63,000 in support of Bob Starr, making it the highest-spending outside group.

Notable mentions

Click on the spending amount for more information on each election.

13. Texas 29th District: $2.3 million
14. Pennsylvania 8th District: $2.3 million
15. Texas 32nd District: $2.2 million
16. North Carolina 2nd District: $2.0 million
17. New York 1st District: $1.9 million
18. Pennsylvania 9th District: $1.8 million
19. Nevada 4th District: $1.7 million
20. Iowa 1st District: $1.7 million
21. New Hampshire 1st District: $1.7 million
22. California 17th District: $1.6 million
23. New York 19th District: $1.4 million
24. Alabama 2nd District: $1.4 million
25. Maine 2nd District: $1.2 million

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In 2014, some House races topped $25 million in total spending — and we’re already well on our way to exceeding that number this year in a number of races.

A few groups to keep an eye on include: the U.S. Chamber of Commerce; EMILY’s List and its super PAC Women Vote!; the National Rifle Association; Club for Growth and other Tea Party groups; House Majority PAC, a super PAC that supports Democrats; One Nation, a dark money nonprofit that supports Republicans; and the Congressional Leadership Fund, a super PAC that supports Republicans.