Delaware County, Iowa

Major highways

• U.S. Highway 20
• Iowa Highway 3
• Iowa Highway 13
• Iowa Highway 38

Adjacent counties

• Buchanan County (west)
• Clayton County (north)
• Dubuque County (east)
• Fayette County (northwest)
• Jones County (southeast)
• Linn County (southwest)

2020 census

As of the 2020 census, the county had a population of 17,488, resulting in a population density of 30.2/sq mi (11.7/km²).^[13]

As of the 2020 census, the median age was 43.5 years. 23.6% of residents were under the age of 18 and 20.5% of residents were 65 years of age or older. For every 100 females there were 101.8 males, and for every 100 females age 18 and over there were 99.6 males age 18 and over.^[13]

As of the 2020 census, the racial makeup of the county was 96.0% White, 0.7% Black or African American, 0.3% American Indian and Alaska Native, 0.3% Asian, <0.1% Native Hawaiian and Pacific Islander, 0.5% from some other race, and 2.3% from two or more races; Hispanic or Latino residents of any race comprised 1.4% of the population.^[14] 97.75% of residents reported being of one race, including 94.60% who were non-Hispanic White and 0.70% who were Black or African American, while 2.74% reported being some other race or more than one race.^[14]

As of the 2020 census, 28.1% of residents lived in urban areas, while 71.9% lived in rural areas.^[15]

As of the 2020 census, there were 7,141 households in the county, of which 27.8% had children under the age of 18 living in them. Of all households, 57.4% were married-couple households, 17.8% were households with a male householder and no spouse or partner present, and 19.7% were households with a female householder and no spouse or partner present. About 27.5% of all households were made up of individuals and 13.0% had someone living alone who was 65 years of age or older. There were 8,100 housing units, of which 11.8% were vacant, leaving 7,141 occupied units; among the occupied units, 80.2% were owner-occupied and 19.8% were renter-occupied. The homeowner vacancy rate was 1.6% and the rental vacancy rate was 6.8%.^[13]

2010 census

The 2010 census recorded a population of 17,764 in the county, with a population density of 30.7/sq mi (11.9/km²). There were 8,028 housing units, of which 7,062 were occupied.^[16]

2000 census

As of the census^[17] of 2000, there were 18,404 people, 6,834 households, and 5,029 families residing in the county. The population density was 32 people per square mile (12 people/km²). There were 7,682 housing units at an average density of 13 units per square mile (5.0 units/km²). The racial makeup of the county was 99.28% White, 0.07% Black or African American, 0.10% Native American, 0.14% Asian, 0.01% Pacific Islander, 0.10% from other races, and 0.30% from two or more races. 0.66% of the population were Hispanic or Latino of any race.

There were 6,834 households, out of which 36.70% had children under the age of 18 living with them, 64.10% were married couples living together, 6.20% had a female householder with no husband present, and 26.40% were non-families. 23.00% of all households were made up of individuals, and 11.20% had someone living alone who was 65 years of age or older. The average household size was 2.66 and the average family size was 3.15.

In the county, the population was spread out, with 29.00% under the age of 18, 7.00% from 18 to 24, 27.60% from 25 to 44, 21.50% from 45 to 64, and 15.00% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 98.40 males. For every 100 females age 18 and over, there were 96.60 males.

The median income for a household in the county was $37,168, and the median income for a family was $43,607. Males had a median income of $30,712 versus $19,685 for females. The per capita income for the county was $17,327. About 6.30% of families and 7.90% of the population were below the poverty line, including 8.50% of those under age 18 and 9.80% of those age 65 or over.

Cities

Townships

Delaware County is divided into these townships:

Unincorporated communities

Population ranking

The population ranking of the following table is based on the 2020 census of Delaware County.^[3]

† county seat