2020 census

The 2020 United States census counted 302 people, 131 households, and 86 families in Delphos.^[7][8] The population density was 509.3 per square mile (196.6/km²). There were 182 housing units at an average density of 306.9 per square mile (118.5/km²).^[8][9] The racial makeup was 95.03% (287) white or European American (94.04% non-Hispanic white), 0.33% (1) black or African-American, 0.66% (2) Native American or Alaska Native, 0.0% (0) Asian, 0.0% (0) Pacific Islander or Native Hawaiian, 0.33% (1) from other races, and 3.64% (11) from two or more races.^[10] Hispanic or Latino of any race was 1.32% (4) of the population.^[11]

Of the 131 households, 21.4% had children under the age of 18; 51.9% were married couples living together; 26.7% had a female householder with no spouse or partner present. 32.1% of households consisted of individuals and 19.1% had someone living alone who was 65 years of age or older.^[8] The average household size was 2.2 and the average family size was 3.1.^[12] The percent of those with a bachelor’s degree or higher was estimated to be 9.6% of the population.^[13]

22.8% of the population was under the age of 18, 5.3% from 18 to 24, 17.9% from 25 to 44, 31.1% from 45 to 64, and 22.8% who were 65 years of age or older. The median age was 49.2 years. For every 100 females, there were 102.7 males.^[8] For every 100 females ages 18 and older, there were 100.9 males.^[8]

The 2016-2020 5-year American Community Survey estimates show that the median household income was $46,118 (with a margin of error of +/- $8,989) and the median family income was $61,667 (+/- $13,961).^[14] Males had a median income of $31,146 (+/- $13,570) versus $29,063 (+/- $9,495) for females. The median income for those above 16 years old was $30,526 (+/- $5,767).^[15] Approximately, 9.4% of families and 15.9% of the population were below the poverty line, including 20.3% of those under the age of 18 and 20.6% of those ages 65 or over.^[16][17]

2010 census

As of the census^[18] of 2010, there were 359 people, 161 households, and 104 families residing in the city. The population density was 579.0 inhabitants per square mile (223.6/km²). There were 222 housing units at an average density of 358.1 per square mile (138.3/km²). The racial makeup of the city was 96.4% White, 0.8% African American, 0.3% Native American, 0.8% from other races, and 1.7% from two or more races. Hispanic or Latino of any race were 2.2% of the population.

There were 161 households, of which 22.4% had children under the age of 18 living with them, 55.9% were married couples living together, 6.8% had a female householder with no husband present, 1.9% had a male householder with no wife present, and 35.4% were non-families. 32.3% of all households were made up of individuals, and 14.3% had someone living alone who was 65 years of age or older. The average household size was 2.23 and the average family size was 2.72.

The median age in the city was 48.7 years. 21.2% of residents were under the age of 18; 6.6% were between the ages of 18 and 24; 19% were from 25 to 44; 27.5% were from 45 to 64; and 25.6% were 65 years of age or older. The gender makeup of the city was 46.8% male and 53.2% female.

2000 census

As of the census^[19] of 2000, there were 469 people, 200 households, and 137 families residing in the city. The population density was 766.8 inhabitants per square mile (296.1/km²). There were 238 housing units at an average density of 389.1 per square mile (150.2/km²). The racial makeup of the city was 98.93% White, 0.21% Native American, and 0.85% from two or more races. Hispanic or Latino of any race were 1.49% of the population.

There were 200 households, out of which 26.0% had children under the age of 18 living with them, 59.0% were married couples living together, 6.0% had a female householder with no husband present, and 31.5% were non-families. 27.0% of all households were made up of individuals, and 16.0% had someone living alone who was 65 years of age or older. The average household size was 2.35 and the average family size was 2.85.

In the city, the population was spread out, with 23.2% under the age of 18, 7.9% from 18 to 24, 22.8% from 25 to 44, 23.0% from 45 to 64, and 23.0% who were 65 years of age or older. The median age was 42 years. For every 100 females, there were 99.6 males. For every 100 females age 18 and over, there were 92.5 males.

The median income for a household in the city was $31,563, and the median income for a family was $39,038. Males had a median income of $27,292 versus $18,438 for females. The per capita income for the city was $14,801. About 8.8% of families and 9.6% of the population were below the poverty line, including 6.7% of those under age 18 and 12.5% of those age 65 or over.