Kelso is a city located in Washington. With a 2020 population of 12,615, it is the 76th largest city in Washington and the 2623rd largest city in the United States. Kelso is currently growing at a rate of 1.25% annually and its population has increased by 5.79% since the most recent census, which recorded a population of 11,925 in 2010. Spanning over 9 miles, Kelso has a population density of 1,551 people per square mile.
The average household income in Kelso is $50,508 with a poverty rate of 27.37%. The median rental costs in recent years comes to $835 per month, and the median house value is $133,900. The median age in Kelso is 35.9 years, 34.3 years for males, and 37 years for females. For every 100 females there are 92.9 males.