Super PACs had their biggest month ever, raising over $55 million in June.

That impressive haul brought Super PACs' total fundraising since Jan 1. 2011 to more than $313 million. As of around June 30, Super PACs had about $110 million in the bank (that total includes groups filing reports due between June 27 and July 13).

Monthly Super PAC contributions and expenditures, as of July 20

Monthly filers reporting the biggest June takes were Restore Our Future ($20.7 million), which backs Mitt Romney; Priorities USA ($6.2 million) which backs Barack Obama; and American Crossroads, ($5.8 million) lead by GOP strategist Karl Rove.

June contributions were led by mega-donors giving seven-figure sums. Eleven individuals were responsible for over $27.6 million in contributions. Top  givers to Republican groups during the month of June included:

• Billionaire casino mogul Sheldon Adelson and his wife Miriam, who together gave $11 million;
• Bob Perry of Perry Homes, who gave $4.1 million;
• Private equity CEO John Childs, who gave $2.5 million;
• College student John Ramsey ($1.11 million), and
• Hedge fund manager Paul Singer $1 million.

Top Democratic donors were:

• Former Qualcomm CEO Irwin Jacobs ($2 million);
• Newsweb founder Fred Eyechaner ($1.95 million);
• Billionaire hedge fund manager George Soros ($1 million);
• Haim Saban, CEO of Saban Capital Group ($1 million), and
• Actor Morgan Freeman ($1 million).

The biggest organizational donors to left-leaning groups were unions: the Service Employees Internation Union, which gave just over $1.9 million; the National Education Assocation ($1 million) and American Federation of State, County and Municipal Employees, AFL-CIO, ($700,000).

Right-leaning organizational donors were lead by corporations: $1.05 million from construction firm TrammellCrow and Crow Holdings; $1 million from Oxbow Carbon, lead by Bill Koch, brother of better-known billionaire industrialists and right-wing philanthropists Charles and David Koch; $1 million from a trio of shell companies lead by Robert T. Brockman (who gave similarly last month), and $925,000 from The Mercury Trust, which the Center for Responsive Politics has linked to private equity firm Fox Paine, headed by Saul Fox.