Petrolia is located in Butler county Pennsylvania with a geographic area of 0.4 square miles. The total population in Petrolia is 179 with 47.5% male and 52.5% female. Children under age 5 represent 4.5% of the population, under age 18 equal 14.0% of the population and over age 65 is 27.9% of the population. The median household income is $48,750, per capita income is $27,089. There are a total of 93 housing units with 68.8% owner occupied. Education includes 59.1% of residents that are high school graduates and 6.5% with a bachelor's degree or higher. The average temperature in Petrolia in the summer is 73 degrees, and in the winter 33 degrees.