It is a full family affair out with great music and plenty of activities for the kids, including face-painting, juggling acts and children's musicians.
There will be about 35 to 40,000 people marching along the grounds before the festival closes Sunday night.
Many people wait all year for this festival.
"It's a trip back in time," says Matt Doyle. "It's like 1969 again."
At 51 years old, the Philadelphia folk festival is the longest continuously running outdoor music festival of its kind in North America.
It is an annual event rich in music, spirit and freedom that has drawn families to this great lawn year after year.
Jessica Bontempo says she's been attending since birth.
"I guess I didn't have a choice when I started, and now I've come to love it," said Jessica.
"I'm second generation, and this is third generation," said Harris VonEssen, who was there with his family.
Jordan's dad hopes his little man keeps the tradition alive.
"This event is about roots music, bringing back the music of the old timers for people who don't get to experience it much," Harris said.
"This is the first year I came, and I am having the best time of my life," said Ethan Cain.
One couple came to event from Wisconsin, and say they immediately felt a sense of community there.
"It's an opportunity for people to set up a little city for the weekend and make society work. It lasts a couple of days, have a great time and then it is time to go home," said Clifton Nesseth.
But before heading home, the crowd of tens of thousands will be camping out, grabbing good grub, and watching several bands unload and unleash their musical spirit on the main stage all weekend long.
"It's freedom; .freedom in its purest form," said Greg Barr.
This year, there are some changes. Instead of having separate afternoon and evening concerts, there will be continuous musical performances both Saturday and Sunday, which also means you buy a single daily ticket for each day of the event.
For more information on what to expect at the folk festival visit the website at the link below.http://www.pfs.org/folk-festival