Pleasantville is a borough in Venango County, Pennsylvania, United States. The population was 841 at the 2020 census, and 892 in 2010. It was an early oil 'boom town', and the population jumped from 291 to 1,598 between 1860 and 1870. But the boom soon passed, and the population shrank to 855 by 1880, and has remained fairly stable since then.