The overwhelming interest expected for the popular pope's visit led to the decision by congressional leaders to broadcast the speech on jumbo-trons for public viewing, a rare event on par with a presidential inauguration.
The 78-year-old pope's address to a joint meeting of Congress is a first by a leader of the Catholic Church.
"The visit of Pope Francis to the U.S. Capitol is a historic moment for the country," said House Speaker John A. Boehner (R-Ohio).
"Given the unprecedented nature of his visit, Pope Francis' address to a joint meeting of Congress will be broadcast live to members of the public on the West Front of the Capitol," he added.
"In addition, Pope Francis has expressed an interest in making a brief appearance on the West Front," said Boehner, a Catholic. "We look forward to welcoming Pope Francis and Americans from all walks of life to our Capitol on Sept. 24."
The pope is scheduled to visit New York and Philadelphia as well as Washington. He is now on a visit to South America, visiting Ecuador, Bolivia and Paraguay.