Nancy Pelosi, D-Calif., the former speaker and now minority leader, has a cross-country schedule, The Hill reported. She has already visited Florida to raise money.
Steny Hoyer, D-Md., the minority whip, has been working the east coast hard.
Democrats seized control of the House in 2006 after 12 years in the minority. But they lost 63 seats to the Republicans in 2010 and need to capture at least 25 in November to regain the majority.
Pelosi says that is doable. But experts disagree.
The Cook Political Report identified 35 seats held by Republicans as vulnerable this year. Capturing all of them would give Pelosi her majority except that the report also identified 25 Democratic seats as vulnerable.