Chelsea Clinton is scheduled to visit Philadelphia this afternoon as she criss-crosses the country campaigning for her mother, Democratic presidential candidate Hillary Rodham Clinton.

The former first daughter, now a financial analyst, will rally younger voters at at an outdoor event at the University of Pennsylvania in West Philadelphia.

The 4:30 p.m. campus stop will be the "first of many trips to Pennsylvania" for Chelsea Clinton and her candidate mother, a campaign spokesman said.

Chelsea Clinton will lead an "Our Voice, Our Future" event at the Wynn Commons outside of Houston Hall, at 3417 Spruce Street.

Hillary Clinton's fortunes hinge on her performance in Pennsylvania's April 22 primary.

Clinton was triumphant over Barack Obama last night in the Ohio and Texas primaries, taking the sting out of 11 straight primary defeats and reviving her bid for the nomination.

"We'll know by the end of the night whether Pennsylvania will be irrelevant or the center of the universe," said Gov. Ed Rendell, just hours before the polls closed in Ohio and Clinton declared victory.

Now a critical political battleground, the Keystone State will be the site for intense campaigning by both Democratic candidates.

Neither Clinton or Obama have enough delegates to clinch the nomination, though Obama maintains a lead after yesterday's races.

Clinton strategists believe that if they can continue to win the big states, the all-important superdelegates will put her over the top.

Last night in Philadelphia supporters from both camps watched the returns at city watering holes.

The staid scene at Finnigan's Wake, where about 60 Clinton supporters watched the returns, was in stark contrast to the raucous energy at the World Café, where 200 Obama supporters were treated to a brass band, speakers, and sign-up sheets.

Contact staff writer Sam Wood at 215-854-2796 or at samwood@phillynews.com.