Democrat Jon Ossoff reported another unprecedented fundraising haul Thursday in the race for Georgia’s 6th Congressional District, collecting an additional $15 million in roughly the last two months in a contest that’s already the most expensive of its kind.

So vast that the report filled about 58,000 pages, Ossoff’s fundraising shattered the quarterly record he set earlier this year, when the former congressional aide astonished the political world by collecting more than $8.3 million. All told, he’s raised about $23.6 million in a quest to flip the suburban Atlanta district.

Republican Karen Handel, his opponent in the June 20 runoff, has yet to report her fundraising totals.

It was not immediately clear how much of Ossoff’s donations came from outside of the district, which stretches from north DeKalb to east Cobb, but his last report showed only about 1 in 20 contributions were from Georgia residents. His campaign said the average donation was $20.49.

The staggering fundraising report underscores the national attention on the contest, considered a must-win by both parties. Costing more than $40 million overall, the race is by far the most expensive U.S. House election in the nation’s history.

An Atlanta Journal-Constitution analysis shows about $25 million spent or reserved for advertising since April 18, when Ossoff narrowly avoided an outright win. Democrats have outspent Republicans by nearly $2 million in the runoff phase.

The fundraising tally also leaves Ossoff open to more attacks that he’s leaning on out-of-state voters, many of them liberals angry with President Donald Trump, to win the seat. Handel and national GOP groups have painted Ossoff as a stooge of Nancy Pelosi, the House Democratic leader, and a product of California values out to “steal” the election.

“Your campaign is being propelled by the most liberal of elements,” Handel said at Tuesday’s debate with Ossoff. “They are not from this district and they don’t represent the values of this district.”

In an interview, Ossoff said the report speaks to “the intensity of grassroots support for the campaign.”

“I’m proud of the fact that it’s small-dollar grassroots fundraising, in stark contrast to my opponent’s campaign, which got bailed out by super PACs from D.C,” he said.

Handel has a history of struggling to raise cash, hobbling her previous campaigns for governor and U.S. Senate. She took in more than $460,000 in her earlier fundraising report - an otherwise respectable take that paled in comparison to Ossoff’s report.

She will far exceed that total this fundraising cycle. She’s had fundraisers with Trump, House Speaker Paul Ryan and other GOP leaders. And she is set to hold another event Friday with Vice President Mike Pence, who is flying into Dobbins Air Reserve Base in the early afternoon.

Her campaign has also been buoyed by a flood of outside spending since her No. 2 finish in the first round of voting. While Handel has reserved about $2.2 million in ad spending through the runoff, GOP groups have reinforced her with more than $9 million in additional spending.

Ossoff is getting backup as well: The Democratic Congressional Campaign Committee has spent $4.3 million in the runoff phase, and other left-leaning groups have chipped in around $500,000. But his fundraising totals means he hasn’t needed as much additional firepower.

In roughly five months, he has out-raised the campaigns of several GOP presidential candidates from last year's race, including John KasichRand Paul and Carly Fiorina. He's amassed more than Ryan and former House Speaker John Boehner did during the last three election cycles. And he far surpassed the $16 million collected by Democrat Michelle Nunn in her 2016 U.S. Senate campaign.

Contrast the flood of money in Georgia with other recent House special elections. Montana’s air wars cost about $10 million, though Democrats only reluctantly helped Rob Quist after weeks of attack ads from GOP groups. And less than $200,000 was spent by outside groups in the Kansas race.

Both of those contests were fought over reliably Republican districts that Trump won by 20 percentage points or more. And in both, national Democrats were squeamish about pumping resources into campaigns they saw as doomed.

Georgia’s 6th District has also long been a GOP stronghold. But Trump won the district by less than 2 points, and Democrats were buoyed by Ossoff’s near-miss of an outright victory on April 18.