Mason City is a city located in Cerro Gordo County Iowa. It is also the county seat of Cerro Gordo County. With a 2020 population of 26,659, it is the 17th largest city in Iowa and the 1449th largest city in the United States . Mason City is currently declining at a rate of -0.51% annually and its population has decreased by -5.06% since the most recent census, which recorded a population of 28,079 in 2010. Mason City reached it's highest population of in . Spanning over 28 miles, Mason City has a population density of 959 people per square mile.
The average household income in Mason City is $65,179 with a poverty rate of 11.93%. The median rental costs in recent years comes to $723 per month, and the median house value is $114,900. The median age in Mason City is 43.3 years, 39.7 years for males, and 45.2 years for females.