Rock Falls is a city in Cerro Gordo County, Iowa, United States, along the Shell Rock River. The population was 150 at the time of the 2020 census. It is part of the Mason City Micropolitan Statistical Area. Geography Rock Falls is located at (43.206223, -93.086145). According to the United States Census Bureau, the city has a total area of , all land. Demographics 2010 census As of the census of 2010, there were 155 people, 68 households, and 50 families residing in the city. The population density was . There were 74 housing units at an average density of . The racial makeup of the city was 98.7% White, 0.6% Asian, and 0.6% from two or more races. There were 68 households, of which 22.1% had children under the age of 18 living with them, 66.2% were married couples living together, 4.4% had a female householder with no husband present, 2.9% had a male householder with no wife present, and 26.5% were non-families. 19.1% of all households were made up of individuals, and 10.3% had someone living alone who was 65 years of age or older. The average household size was 2.28 and the average family size was 2.64. The median age in the city was 49.5 years. 14.8% of residents were under the age of 18; 4.7% were between the ages of 18 and 24; 24.5% were from 25 to 44; 29.1% were from 45 to 64; and 27.1% were 65 years of age or older. The gender makeup of the city was 51.0% male and 49.0% female. 2000 census As of the census of 2000, there were 170 people, 68 households, and 55 families residing in the city. The population density was . There were 69 housing units at an average density of . The racial makeup of the city was 100.00% White. Hispanic or Latino of any race were 0.59% of the population. There were 68 households, out of which 32.4% had children under the age of 18 living with them, 69.1% were married couples living together, 5.9% had a female householder with no husband present, and 19.1% were non-families. 17.6% of all households were made up of individuals, and 8.8% had someone living alone who was 65 years of age or older. The average household size was 2.50 and the average family size was 2.76. In the city, the population was spread out, with 22.4%