2020 census

The 2020 United States census counted 480 people, 207 households, and 133 families in La Harpe.^[9][10] The population density was 602.3 per square mile (232.5/km²). There were 234 housing units at an average density of 293.6 per square mile (113.4/km²).^[10][11] The racial makeup was 92.71% (445) white or European American (91.88% non-Hispanic white), 0.21% (1) black or African-American, 1.88% (9) Native American or Alaska Native, 0.42% (2) Asian, 0.0% (0) Pacific Islander or Native Hawaiian, 0.42% (2) from other races, and 4.38% (21) from two or more races.^[12] Hispanic or Latino of any race was 2.29% (11) of the population.^[13]

Of the 207 households, 28.5% had children under the age of 18; 47.3% were married couples living together; 17.9% had a female householder with no spouse or partner present. 29.5% of households consisted of individuals and 8.7% had someone living alone who was 65 years of age or older.^[10] The average household size was 2.5 and the average family size was 2.9.^[14] The percent of those with a bachelor’s degree or higher was estimated to be 5.6% of the population.^[15]

19.8% of the population was under the age of 18, 8.8% from 18 to 24, 21.9% from 25 to 44, 30.2% from 45 to 64, and 19.4% who were 65 years of age or older. The median age was 44.7 years. For every 100 females, there were 103.4 males.^[10] For every 100 females ages 18 and older, there were 96.4 males.^[10]

The 2016-2020 5-year American Community Survey estimates show that the median household income was $34,583 (with a margin of error of +/- $4,323) and the median family income was $43,125 (+/- $18,550).^[16] Males had a median income of $27,292 (+/- $7,377) versus $17,130 (+/- $3,177) for females. The median income for those above 16 years old was $21,797 (+/- $5,632).^[17] Approximately, 10.1% of families and 12.5% of the population were below the poverty line, including 20.5% of those under the age of 18 and 8.9% of those ages 65 or over.^[18][19]

2010 census

As of the census^[20] of 2010, there were 578 people, 234 households, and 161 families residing in the city. The population density was 704.9 inhabitants per square mile (272.2/km²). There were 273 housing units at an average density of 332.9 per square mile (128.5/km²). The racial makeup of the city was 93.6% White, 1.4% African American, 1.2% Native American, 0.9% Asian, 1.0% from other races, and 1.9% from two or more races. Hispanic or Latino of any race were 1.6% of the population.

There were 234 households, of which 28.6% had children under the age of 18 living with them, 49.6% were married couples living together, 12.0% had a female householder with no husband present, 7.3% had a male householder with no wife present, and 31.2% were non-families. 26.1% of all households were made up of individuals, and 12% had someone living alone who was 65 years of age or older. The average household size was 2.47 and the average family size was 2.91.

The median age in the city was 42.2 years. 22.3% of residents were under the age of 18; 9% were between the ages of 18 and 24; 24.1% were from 25 to 44; 27.9% were from 45 to 64; and 16.8% were 65 years of age or older. The gender makeup of the city was 52.1% male and 47.9% female.

2000 census

As of the census^[21] of 2000, there were 706 people, 268 households, and 191 families residing in the city. The population density was 819.4 inhabitants per square mile (316.4/km²). There were 298 housing units at an average density of 345.9 per square mile (133.6/km²). The racial makeup of the city was 93.77% White, 0.99% African American, 2.12% Native American, and 3.12% from two or more races. Hispanic or Latino of any race were 0.85% of the population.

There were 268 households, out of which 35.8% had children under the age of 18 living with them, 57.1% were married couples living together, 9.7% had a female householder with no husband present, and 28.4% were non-families. 23.5% of all households were made up of individuals, and 11.2% had someone living alone who was 65 years of age or older. The average household size was 2.63 and the average family size was 3.08.

In the city, the population was spread out, with 28.6% under the age of 18, 9.8% from 18 to 24, 29.6% from 25 to 44, 21.4% from 45 to 64, and 10.6% who were 65 years of age or older. The median age was 34 years. For every 100 females, there were 103.5 males. For every 100 females age 18 and over, there were 100.8 males.

The median income for a household in the city was $24,219, and the median income for a family was $32,981. Males had a median income of $22,102 versus $16,058 for females. The per capita income for the city was $12,196. About 8.9% of families and 13.4% of the population were below the poverty line, including 16.1% of those under age 18 and 11.8% of those age 65 or over.