City officials will join leaders from neighboring Tinicum Township, Delaware County and the Interboro School District to discuss the deal at a news conference Monday.
A Delaware County spokeswoman says the agreement will allow the expansion to move forward "while maintaining the integrity of Tinicum Township and its businesses."
The $6.4 billion project is designed to make the airport more competitive by reducing delays and adding capacity and services.
The airport is one of the nation's busiest. It served more than 30 million passengers last year and accommodated nearly 433,000 takeoffs and landings.