2020 census

The 2020 United States census counted 428 people, 169 households, and 117 families in Assaria.^[9][10] The population density was 1,829.1 per square mile (706.2/km²). There were 176 housing units at an average density of 752.1 per square mile (290.4/km²).^[10][11] The racial makeup was 95.79% (410) white or European American (94.16% non-Hispanic white), 0.7% (3) black or African-American, 0.0% (0) Native American or Alaska Native, 0.0% (0) Asian, 0.0% (0) Pacific Islander or Native Hawaiian, 0.93% (4) from other races, and 2.57% (11) from two or more races.^[12] Hispanic or Latino of any race was 3.74% (16) of the population.^[13]

Of the 169 households, 33.7% had children under the age of 18; 58.0% were married couples living together; 18.3% had a female householder with no spouse or partner present. 23.1% of households consisted of individuals and 12.4% had someone living alone who was 65 years of age or older.^[10] The average household size was 2.6 and the average family size was 2.9.^[14] The percent of those with a bachelor’s degree or higher was estimated to be 19.4% of the population.^[15]

26.4% of the population was under the age of 18, 5.1% from 18 to 24, 24.8% from 25 to 44, 26.4% from 45 to 64, and 17.3% who were 65 years of age or older. The median age was 40.7 years. For every 100 females, there were 101.9 males.^[10] For every 100 females ages 18 and older, there were 105.9 males.^[10]

The 2016-2020 5-year American Community Survey estimates show that the median household income was $69,545 (with a margin of error of +/- $16,322) and the median family income was $69,688 (+/- $14,136).^[16] Males had a median income of $52,000 (+/- $12,479) versus $33,125 (+/- $8,594) for females. The median income for those above 16 years old was $38,036 (+/- $5,762).^[17] Approximately, 3.2% of families and 7.7% of the population were below the poverty line, including 8.3% of those under the age of 18 and 4.1% of those ages 65 or over.^[18][19]

2010 census

As of the census^[20] of 2010, there were 413 people, 159 households, and 122 families living in the city. The population density was 2,173.7 inhabitants per square mile (839.3/km²). There were 171 housing units at an average density of 900.0 per square mile (347.5/km²). The racial makeup of the city was 98.3% White, 0.2% Native American, and 1.5% from two or more races. Hispanic or Latino of any race were 1.9% of the population.

There were 159 households, of which 34.6% had children under the age of 18 living with them, 65.4% were married couples living together, 6.3% had a female householder with no husband present, 5.0% had a male householder with no wife present, and 23.3% were non-families. 18.2% of all households were made up of individuals, and 7.6% had someone living alone who was 65 years of age or older. The average household size was 2.60 and the average family size was 2.95.

The median age in the city was 39.7 years. 27.4% of residents were under the age of 18; 6.3% were between the ages of 18 and 24; 22.6% were from 25 to 44; 30.4% were from 45 to 64; and 13.3% were 65 years of age or older. The gender makeup of the city was 50.8% male and 49.2% female.

2000 census

As of the census^[21] of 2000, there were 438 people, 153 households, and 123 families living in the city. The population density was 2,220.0 inhabitants per square mile (857.1/km²). There were 160 housing units at an average density of 811.0 per square mile (313.1/km²). The racial makeup of the city was 95.43% White, 1.14% Native American, 0.23% Asian, 2.05% from other races, and 1.14% from two or more races. Hispanic or Latino of any race were 3.65% of the population.

There were 153 households, out of which 43.8% had children under the age of 18 living with them, 72.5% were married couples living together, 7.2% had a female householder with no husband present, and 19.0% were non-families. 15.7% of all households were made up of individuals, and 4.6% had someone living alone who was 65 years of age or older. The average household size was 2.86 and the average family size was 3.23.

In the city, the population was spread out, with 32.4% under the age of 18, 7.1% from 18 to 24, 29.9% from 25 to 44, 20.3% from 45 to 64, and 10.3% who were 65 years of age or older. The median age was 35 years. For every 100 females, there were 95.5 males. For every 100 females age 18 and over, there were 85.0 males.

The median income for a household in the city was $44,792, and the median income for a family was $45,833. Males had a median income of $34,063 versus $24,375 for females. The per capita income for the city was $19,381. None of the families and 1.9% of the population were living below the poverty line, including no under eighteens and 2.2% of those over 64.