"It's a long road to 1600 Pennsylvania Ave. and it runs right through the heart of Pennsylvania," she told supporters in Philadelphia.
"I'm in this race to fight for you ... You know you can count on me to stand up strong for you every single day in the White House."
Clinton commended Obama and his campaign, saying they are in many ways "on this journey together

Tuesday's projected victory follows Clinton's wins in other big states such as Ohio, New York and California.