Mercersburg is located in Franklin county Pennsylvania with a geographic area of 0.9 square miles. The total population in Mercersburg is 1,673 with 45.6% male and 54.4% female. Children under age 5 represent 4.1% of the population, under age 18 equal 13.5% of the population and over age 65 is 20.9% of the population. The median household income is $51,333, per capita income is $31,636. There are a total of 776 housing units with 53.6% owner occupied. Education includes 35.3% of residents that are high school graduates and 23.6% with a bachelor's degree or higher. The average temperature in Mercersburg in the summer is 73 degrees, and in the winter 33 degrees.