Hillary Clinton is raising huge amounts of cash for the Democratic National Committee and state parties, according to figures released by her campaign on Wednesday, laying the groundwork for a substantial investment in swing states during the fall.

August was Mrs. Clinton’s most successful fund-raising month so far, as she crisscrossed the country on a money hunt that took her to dozens of events in the summer locales of the wealthy and the well-to-do. Her efforts brought in $143 million for her campaign and for Democratic organizations, according to her campaign. That is far more than the $90 million haul Mrs. Clinton and the Democrats reported in July.

But most of the increase is coming in the form of contributions earmarked for Democratic Party organizations.

Mrs. Clinton has been making particularly avid use of new fund-raising limits ushered in by court rulings and new campaign finance rules. Her largest donors are writing checks for $350,000 or more, effectively a combined contribution to her campaign, the D.N.C. and dozens of state parties participating in her joint fund-raising effort.