Rock Rapids is a city located in Lyon County Iowa. It is also the county seat of Lyon County. With a 2020 population of 2,474, it is the 138th largest city in Iowa and the 6863rd largest city in the United States . Rock Rapids is currently declining at a rate of -0.96% annually and its population has decreased by -2.94% since the most recent census, which recorded a population of 2,549 in 2010. Rock Rapids reached it's highest population of in . Spanning over 4 miles, Rock Rapids has a population density of 584 people per square mile.
The average household income in Rock Rapids is $72,644 with a poverty rate of 4.61%. The median rental costs in recent years comes to $561 per month, and the median house value is $140,900. The median age in Rock Rapids is 39.4 years, 36.3 years for males, and 42.8 years for females.