Seneca is located in Grant county Oregon with a geographic area of 0.8 square miles. The total population in Seneca is 242 with 45.0% male and 55.0% female. Children under age 5 represent 4.1% of the population, under age 18 equal 15.7% of the population and over age 65 is 43.0% of the population. The median household income is $46,136, per capita income is $26,421. There are a total of 124 housing units with 78.2% owner occupied. Education includes 37.1% of residents that are high school graduates and 9.7% with a bachelor's degree or higher. The average temperature in Seneca in the summer is 57 degrees, and in the winter 35 degrees.