Ottawa is a city located in Franklin County Kansas. It is also the county seat of Franklin County. With a 2020 population of 12,216, it is the 29th largest city in Kansas and the 2680th largest city in the United States . Ottawa is currently declining at a rate of -0.16% annually and its population has decreased by -3.42% since the most recent census, which recorded a population of 12,649 in 2010. Ottawa reached it's highest population of 12,642 in 2010. Spanning over 10 miles, Ottawa has a population density of 1,238 people per square mile.
The average household income in Ottawa is $59,384 with a poverty rate of 13.92%. The median rental costs in recent years comes to $792 per month, and the median house value is $109,000. The median age in Ottawa is 35.5 years, 34.3 years for males, and 36.6 years for females.