Union city is located in Darke county Ohio with a geographic area of 8.3 square miles. The total population in Union city is 6,777 with 52.2% male and 47.8% female. Children under age 5 represent 4.6% of the population, under age 18 equal 26.3% of the population and over age 65 is 18.3% of the population. The median household income is $63,657, per capita income is $30,575. There are a total of 2,705 housing units with 73.5% owner occupied. Education includes 42.3% of residents that are high school graduates and 23.3% with a bachelor's degree or higher. The average temperature in Union city in the summer is 71 degrees, and in the winter 32 degrees.