2020 census

The 2020 United States census^[8] counted 7,643 people, 2,672 households, and 1,705 families in Seward. The population density was 1,713.7 per square mile (662.3/km²). There were 2,824 housing units at an average density of 633.2 per square mile (244.7/km²). The racial makeup was 93.31% (7,132) white, 0.94% (72) black or African-American, 0.3% (23) Native American, 0.39% (30) Asian, 0.04% (3) Pacific Islander, 1.06% (81) from other races, and 3.95% (302) from two or more races. Hispanic or Latino of any race was 3.0% (213) of the population.

Of the 2,672 households, 30.7% had children under the age of 18; 53.1% were married couples living together; 23.8% had a female householder with no husband present. 27.4% of households consisted of individuals and 15.8% had someone living alone who was 65 years of age or older. The average household size was 2.3 and the average family size was 2.9.

20.5% of the population was under the age of 18, 20.3% from 18 to 24, 20.1% from 25 to 44, 18.5% from 45 to 64, and 14.9% who were 65 years of age or older. The median age was 31.6 years. For every 100 females, the population had 101.8 males. For every 100 females ages 18 and older, there were 98.9 males.

The 2016-2020 5-year American Community Survey^[9] estimates show that the median household income was $66,190 (with a margin of error of +/- $7,523) and the median family income $92,260 (+/- $6,779). Males had a median income of $40,676 (+/- $8,526) versus $20,585 (+/- $8,626) for females. The median income for those above 16 years old was $27,047 (+/- $3,169). Approximately, 4.3% of families and 9.3% of the population were below the poverty line, including 4.1% of those under the age of 18 and 3.8% of those ages 65 or over.

2010 census

At the 2010 census there were 6,964 people, 2,521 households, and 1,653 families living in the city. The population density was 1,630.9 inhabitants per square mile (629.7/km²). There were 2,796 housing units at an average density of 654.8 per square mile (252.8/km²). The racial makeup of the city was 96.8% White, 0.6% African American, 0.4% Native American, 0.6% Asian, 0.3% from other races, and 1.4% from two or more races. Hispanic or Latino people of any race were 1.9%.^[10]

Of the 2,521 households 32.1% had children under the age of 18 living with them, 55.0% were married couples living together, 7.3% had a female householder with no husband present, 3.2% had a male householder with no wife present, and 34.4% were non-families. 30.2% of households were one person and 15.4% were one person aged 65 or older. The average household size was 2.39 and the average family size was 2.98.

The median age was 32.4 years. 22.6% of residents were under the age of 18; 18.8% were between the ages of 18 and 24; 21.5% were from 25 to 44; 22% were from 45 to 64; and 15.1% were 65 or older. The gender makeup of the city was 48.1% male and 51.9% female.

2000 census

At the 2000 census, there were 6,319 people, 2,281 households, and 1,494 families living in the city. The population density was 1,930.9 inhabitants per square mile (745.5/km²). There were 2,415 housing units at an average density of 737.9 per square mile (284.9/km²). The racial makeup of the city was 97.97% White, 0.46% African American, 0.13% Native American, 0.47% Asian, 0.36% from other races, and 0.60% from two or more races. Hispanic or Latino people of any race were 0.98% of the population.

Of the 2,281 households 31.7% had children under the age of 18 living with them, 55.6% were married couples living together, 7.3% had a female householder with no husband present, and 34.5% were non-families. 29.8% of households were one person and 16.2% were one person aged 65 or older. The average household size was 2.39 and the average family size was 2.99.

The age distribution was 22.6% under the age of 18, 20.1% from 18 to 24, 22.9% from 25 to 44, 17.9% from 45 to 64, and 16.5% 65 or older. The median age was 32 years. For every 100 females, there were 90.7 males. For every 100 females age 18 and over, there were 86.4 males.

The median household income was $41,264, and the median family income was $54,808. Males had a median income of $33,828 versus $22,231 for females. The per capita income for the city was $17,668. About 4.1% of families and 6.6% of the population were below the poverty line, including 4.6% of those under age 18 and 5.3% of those age 65 or over.