The previous seven gatherings, starting in 1994, were in Rome (twice); Rio de Janeiro; Manila, the Philippines; Valencia, Spain; Mexico City; and Milan, Italy.
Gov. Corbett and Mayor Nutter will serve as honorary co-chairs of the event, said Archbishop Charles J. Chaput, head of the Archdiocese of Philadelphia.
Although it was too early to estimate the full economic impact, city tourism and convention officials said the exposure Philadelphia is expected to receive from the world media will have a huge value.
"This is an honor for Philadelphia, to take a global stage as host of the World Meeting of Families by the Holy Father," said Jack Ferguson, president and chief executive of the Philadelphia Convention and Visitors Bureau.
The bureau books the Convention Center, where attendees will conduct their meetings and panels.
"We are working closely with the organizers and expect this event to have a very big impact on Philadelphia's entire region and its travel industry, with visitors coming from across the nation and around the world," he said.
Estimates on economic impact from the event will be released in a few weeks, Ferguson said. The event's venues will be announced in the near future.
The convention is expected to attract tens of thousands of Catholics and their families from around the world.
At the 2012 gathering in Milan, 153 nations were represented. More than one million attended the Mass celebrated by Pope Benedict XVI.
Meryl Levitz, of the Greater Philadelphia Tourism Marketing Corp., likened the event to the Republican National Convention here in 2000.
She said it will require the same planning and logistics to ensure that the tens of thousands who make the trip will leave with a positive impression and want to return as visitors.
"Because it [the event] is family-focused, Philly has the opportunity to show off what families love about us - our history, museums, parks, and great experiences, as well as our meeting and convention capabilities," Levitz said. ". . . The systems that we put together for the RNC - volunteers, safety, communications, shopping and dining options, etc. - will all be needed, and it will again bring together the tristate region."
A huge unknown is whether the successor to Pope Benedict, who has resigned effective Thursday, will make an appearance at the 2015 event, which local officials said would likely increase attendance and the economic impact.
"Of course, the total impact will depend on whether or not the new pope attends the meeting," said Ed Grose, executive director of the 91-member Greater Philadelphia Hotel Association. "If he does attend, hotels throughout the entire Delaware Valley will do well."
The pope has historically attended the gathering.
"It's our sincere hope to welcome [the pope] here to Philadelphia in 2015," said Ken Gavin, spokesman for the archdiocese.
Contact Suzette Parmley at 215-854-2855 or firstname.lastname@example.org.