But the single largest donation so far in this race has been on the other side of the ballot.
Corbett, widely described as one of the nation's most politically vulnerable incumbent governors, got $1.6 million from the Republican Governors Association on April 30, the records show.
The only other member of the seven-figure club in the 2014 election had been Tim Grumbacher, board chairman and former CEO of the Bon-Ton department store chain.
Grumbacher gave $1 million to Democrat Tom Wolf. (Wolf and Grumbacher are both from York County, and Wolf once served on Bon-Ton's board).
Other candidates were also buoyed by big-ticket donors.
U.S. Rep. Allyson Schwartz of Montgomery County logged $150,000 more from her most generous donor, Emily's List, an organization that supports pro-choice candidates. The group has given a total of more than $600,000 to Schwartz's campaign.
Mark Bergman, a Schwartz campaign spokesman, said that the average contribution had been $250 and that contributions had come from every county in the state.
Dan Fee, a Democratic consultant who is unaffiliated with any of the candidates, said the current big-ticket contributors were pretty typical.
"The names change, but the concept of big donors does not," said Fee, who worked on Ed Rendell's gubernatorial campaigns.
Other six-figure donations include $250,000 to Corbett's campaign from John S. Middleton, a Bryn Mawr philanthropist and part-owner of the Phillies. Middleton, who rarely grants interviews, did not respond to The Inquirer's request for comment.
Al Lord, a former Sallie Mae CEO, gave $500,000 to State Treasurer Rob McCord's campaign. He told The Inquirer this year that he believed McCord, a Democrat, would do the best job of rebuilding Pennsylvania State University's reputation after the Jerry Sandusky scandal.
Katie McGinty, former secretary of the Pennsylvania Department of Environmental Protection and a White House aide during the Clinton administration, got $200,000 in donations and a $100,000 loan last year from Brian Duperreault, a New York insurance executive. He and McGinty are graduates of St. Joseph's University.
"These people are friends, some of whom she's known for 20, 25 years," McGinty campaign spokesman Mike Mikus said of the bigger donors. "They're personal friends and professional colleagues who think she'd be a great governor."
Political experts aren't surprised by the big checks rolling in this year.
"You see the continued need and importance of raising this type of money to be competitive," said Chris Borick, a political science professor at Muhlenberg College. "There is a price for entry."
G. Terry Madonna, a political scientist and pollster at Franklin and Marshall College, said the only new aspect of the race so far was the self-funding by some candidates, most notably Wolf - who put $10 million of his own money into his campaign, spending a lot of it on TV ads.
"We've never seen anything like that," Madonna said. "Would he have been able to be anywhere without it, just raising $3 million? The answer is no."
This article contains information from the Associated Press.