Castlewood is a city located in South Dakota. With a 2020 population of 656, it is the 97th largest city in South Dakota and the 12169th largest city in the United States. Castlewood is currently growing at a rate of 1.39% annually and its population has increased by 4.63% since the most recent census, which recorded a population of 627 in 2010. Spanning over 1 miles, Castlewood has a population density of 570 people per square mile.
The average household income in Castlewood is $69,583 with a poverty rate of 5.14%. The median rental costs in recent years comes to $625 per month, and the median house value is $119,700. The median age in Castlewood is 29.2 years, 29.3 years for males, and 28.8 years for females. For every 100 females there are 97.3 males.