2020 census

The 2020 United States census counted 1,313 people, 584 households, and 348 families in Harper.^[9][10] The population density was 809.0 per square mile (312.4/km²). There were 741 housing units at an average density of 456.6 per square mile (176.3/km²).^[10][11] The racial makeup was 76.77% (1,008) white or European American (73.95% non-Hispanic white), 0.23% (3) black or African-American, 2.36% (31) Native American or Alaska Native, 0.23% (3) Asian, 0.08% (1) Pacific Islander or Native Hawaiian, 12.8% (168) from other races, and 7.54% (99) from two or more races.^[12] Hispanic or Latino of any race was 19.95% (262) of the population.^[13]

Of the 584 households, 30.0% had children under the age of 18; 41.4% were married couples living together; 27.6% had a female householder with no spouse or partner present. 35.6% of households consisted of individuals and 18.2% had someone living alone who was 65 years of age or older.^[10] The average household size was 2.1 and the average family size was 2.8.^[14] The percent of those with a bachelor’s degree or higher was estimated to be 7.1% of the population.^[15]

25.6% of the population was under the age of 18, 6.3% from 18 to 24, 23.7% from 25 to 44, 22.7% from 45 to 64, and 21.7% who were 65 years of age or older. The median age was 39.6 years. For every 100 females, there were 98.0 males.^[10] For every 100 females ages 18 and older, there were 96.6 males.^[10]

The 2016-2020 5-year American Community Survey estimates show that the median household income was $51,750 (with a margin of error of +/- $2,828) and the median family income was $75,917 (+/- $18,670).^[16] Males had a median income of $39,564 (+/- $6,208) versus $21,458 (+/- $1,773) for females. The median income for those above 16 years old was $33,750 (+/- $7,955).^[17] Approximately, 4.4% of families and 11.4% of the population were below the poverty line, including 11.7% of those under the age of 18 and 12.0% of those ages 65 or over.^[18][19]

2010 census

As of the census^[20] of 2010, there were 1,473 people, 624 households, and 385 families living in the city. The population density was 903.7 inhabitants per square mile (348.9/km²). There were 742 housing units at an average density of 455.2 per square mile (175.8/km²). The racial makeup of the city was 92.2% White, 0.2% African American, 1.3% Native American, 0.1% Asian, 0.5% Pacific Islander, 4.8% from other races, and 1.0% from two or more races. Hispanic or Latino of any race were 10.0% of the population.

There were 624 households, of which 30.9% had children under the age of 18 living with them, 47.0% were married couples living together, 8.7% had a female householder with no husband present, 6.1% had a male householder with no wife present, and 38.3% were non-families. 34.5% of all households were made up of individuals, and 15.4% had someone living alone who was 65 years of age or older. The average household size was 2.33 and the average family size was 2.95.

The median age in the city was 40.3 years. 25.1% of residents were under the age of 18; 8% were between the ages of 18 and 24; 22.8% were from 25 to 44; 25.1% were from 45 to 64; and 19.1% were 65 years of age or older. The gender makeup of the city was 50.2% male and 49.8% female.

2000 census

As of the census^[21] of 2000, there were 1,567 people, 675 households, and 417 families living in the city. The population density was 1,219.0 inhabitants per square mile (470.7/km²). There were 787 housing units at an average density of 612.2 per square mile (236.4/km²). The racial makeup of the city was 97.57% White, 0.13% African American, 0.64% Native American, 0.57% from other races, and 1.08% from two or more races. Hispanic or Latino of any race were 1.21% of the population.

There were 675 households, out of which 28.0% had children under the age of 18 living with them, 51.3% were married couples living together, 8.7% had a female householder with no husband present, and 38.2% were non-families. 35.3% of all households were made up of individuals, and 18.1% had someone living alone who was 65 years of age or older. The average household size was 2.29 and the average family size was 2.98.

In the city, the population was spread out, with 26.0% under the age of 18, 6.4% from 18 to 24, 22.0% from 25 to 44, 23.9% from 45 to 64, and 21.7% who were 65 years of age or older. The median age was 42 years. For every 100 females, there were 93.5 males. For every 100 females age 18 and over, there were 93.2 males.

The median income for a household in the city was $30,272, and the median income for a family was $40,761. Males had a median income of $29,583 versus $19,779 for females. The per capita income for the city was $16,543. About 6.9% of families and 9.5% of the population were below the poverty line, including 11.0% of those under age 18 and 6.4% of those age 65 or over.