The Oil Region is located in rural northwestern Pennsylvania.
It includes all 683 square miles of Venango County plus the southeastern corner of Crawford County comprising the city of Titusville, Oil Creek Township, and the borough of Hydetown for a total of 720 square miles.
Adjacent counties are Warren (north), Forest (northeast), Clarion (east), Butler (south), and Mercer (west), with Erie to the north of Crawford County.
According to the 2022 census, the population of Venango County was 49,777 residents and in eastern Crawford County 7,692 people resided in the City of Titusville, Oil Creek Township, and Hydetown Borough, bringing the population of the Oil Region to an estimated 57,469 people. Oil City is home to more than 9,500 people. Franklin, the Venango County seat, has a population of 5,991. Its suburb of Sugarcreek Borough has nearly another 5,000 residents and more than 6,250 people reside in nearby Cranberry Township.