Council members approved the ordinance Tuesday evening. Much of the land in question is located in Moon and Findlay townships.
The Pittsburgh Tribune Review reports the measure was approved in a 9-to-4 vote with one abstention.
The lease will enable drilling to take place on county-owned land for the extraction of "oil, gas, natural gas liquids, and other materials," according to a statement from the county.
With the ordinance, the Allegheny County Airport Authority has entered into a 20-year agreement with Cecil-based energy provider Consol Energy.
Under the agreement, Consol has agreed to pay the airport authority a lump sum of $50 million in addition to an 18 percent royalty on annual natural gas proceeds generated from airport land.
The deal could net more than $500 million for the airport.
Before drilling can take place, Consol's drilling sites must be reviewed and approved by Findlay and Moon officials to ensure compliance with local zoning regulations.
The neighboring airport communities permit drilling, though no shale extraction has yet taken place in the municipalities.
The Federal Aviation Administration mandates that all gas proceeds from airport land must be used towards improving the airport, including its properties and facilities.
Allegheny County Executive Rich Fitzgerald endorsed the deal as a potential economic generator for the airport corridor.
In a statement issued by Fitzgerald's office, the county executive said:
"The vote by county council earlier this evening is exciting news for Allegheny County. It isn't often that the county is able to announce a billion dollar investment, but that's exactly what the council's action allows us to do tonight.
While the revenues from the deal will go directly to the airport, the county benefits too—by reducing business costs for airlines and increasing our airport's competitiveness, creating a new source of revenue for the airport to make capital improvements, and perhaps most importantly, allowing additional investment in the economic development opportunities in the airport corridor."