Seneca is a city located in South Dakota. With a 2020 population of 38, it is the 289th largest city in South Dakota and the 19227th largest city in the United States. Seneca is currently declining at a rate of 0.00% annually and its population has decreased by 0.00% since the most recent census, which recorded a population of 38 in 2010. Seneca reached it's highest population of 39 in 2012. Spanning over 0 miles, Seneca has a population density of 91 people per square mile.
The average household income in Seneca is $62,467 with a poverty rate of 7.69%. The median rental costs in recent years comes to - per month, and the median house value is -. The median age in Seneca is 67.7 years, 67.2 years for males, and 72.3 years for females. For every 100 females there are 100.0 males.