Monongahela is located in Allegheny county Pennsylvania with a geographic area of 1.9 square miles. The total population in Monongahela is 4,142 with 51.2% male and 48.8% female. Children under age 5 represent 5.7% of the population, under age 18 equal 21.6% of the population and over age 65 is 15.8% of the population. The median household income is $52,222, per capita income is $25,744. There are a total of 1,740 housing units with 65.1% owner occupied. Education includes 39.3% of residents that are high school graduates and 20.7% with a bachelor's degree or higher. The average temperature in Monongahela in the summer is degrees, and in the winter degrees.