2020 census As of the
2020 census, Island City had a population of 1,144. The median age was 43.3 years. 22.7% of residents were under the age of 18 and 23.1% were 65 years of age or older. For every 100 females there were 93.9 males, and for every 100 females age 18 and over there were 88.5 males age 18 and over. There were 470 households in Island City, of which 28.5% had children under the age of 18 living in them. Of all households, 54.0% were married-couple households, 12.8% were households with a male householder and no spouse or partner present, and 25.7% were households with a female householder and no spouse or partner present. About 23.8% of all households were made up of individuals and 14.1% had someone living alone who was 65 years of age or older. There were 399 households, of which 29.6% had children under the age of 18 living with them. 62.2% were
married couples living together, 10.0% had a female householder with no husband present, 2.5% had a male householder with no wife present and 25.3% were non-families. 21.3% of all households were made up of individuals, and 10.8% had someone living alone who was 65 years of age or older. The average household size was 2.45 and the average family size was 2.81. The median age was 43.5 years. 23.8% of residents were under the age of 18; 6.2% were between the ages of 18 and 24; 22.4% were from 25 to 44; 27.3% were from 45 to 64; and 20.6% were 65 years of age or older. The gender make-up was 49.4% male and 50.6% female.
2000 census At the 2000 census, there were 916 people, 357 households and 280 families living in the city. The population density was . There were 375 housing units at an average density of . The racial make-up was 95.41% White, 0.22% African American, 1.20% Native American, 0.76% Asian, 0.33% Pacific Islander, 1.09% from other races, and 0.98% from two or more races. Hispanic or Latino of any race were 2.07% of the population. There were 357 households, of which 31.9% had children under the age of 18 living with them, 70.6% were married couples living together, 6.4% had a female householder with no husband present, and 21.3% were non-families. 17.9% of all households were made up of individuals, and 9.2% had someone living alone who was 65 years of age or older. The average household size was 2.57 and the average family size was 2.87. 23.7% of the population were under the age of 18, 7.1% from 18 to 24, 24.7% from 25 to 44, 28.2% from 45 to 64, and 16.4% who were 65 years of age or older. The median age was 42 years. For every 100 females, there were 98.3 males. For every 100 females age 18 and over, there were 94.2 males. The
median household income was $43,977 and the median family income was $49,327. Males had a median income of $39,250 and females $20,486. The
per capita income was $19,138. About 3.3% of families and 5.9% of the population were below the
poverty line, including 3.9% of those under age 18 and 9.3% of those age 65 or over. ==Education==