Franklin is a city in Venango County, Pennsylvania, United States. The population was estimated 7,212 in the 2000 census. It is the county seat of Venango County. According to the United States Census Bureau, the city has a total area of 4.7square miles (12Square kilometers), of which 4.6square miles (12Square kilometers) is land and 0.1square miles (0.26Square kilometers) (1.70%) is water. As of the census of 2000, there were 7,212people, 3,030households, and 1,824families residing in the city. The population density was 1,560.2people per square mile (602.7Square kilometers). There were 3,281housing units at an average density of 709.8per square mile (274.2Square kilometers).