An Obama campaign volunteer high-fives people waiting in line for an Obama rally at George Mason University, October 19, in Fairfax, Va. (Chip Somodevilla/Getty)

President Obama is preparing to rally a key part of his base in a critical swing state on Friday, speaking to students and supporters at George Mason University in Northern Virginia.

Thousands of people, of mixed races and various ages, were waiting for the president on the university's recreational sports field, holding Obama signs and chanting "four more years!"

Reflecting his urgent push for female voters, a crucial bloc that could decide the election, Obama will speak from a podium draped with two blue signs saying "Women's Health Security."

Recent polls have shown Republican challenger Mitt Romney gaining on Obama in support from female voters. Obama is also counting on a heavy turnout from young voters, another key part of the coalition that elected him in 2008.