Marshfield is located at . According to the United States Census Bureau, the city has a total area of, all land.
Demographics
2010 census
At the 2010 census there were 6,633 people, 2,605 households, and 1,756 families living in the city. The population density was. There were 2,918 housing units at an average density of. The racial makeup of the city was 96.5% White, 0.4% African American, 0.8% Native American, 0.2% Asian, 0.5% from other races, and 1.7% from two or more races. Hispanic or Latino of any race were 1.7%. Of the 2,605 households 37.0% had children under the age of 18 living with them, 49.0% were married couples living together, 14.0% had a female householder with no husband present, 4.4% had a male householder with no wife present, and 32.6% were non-families. 28.9% of households were one person and 14.8% were one person aged 65 or older. The average household size was 2.47 and the average family size was 3.04. The median age was 36.4 years. 27.6% of residents were under the age of 18; 8.5% were between the ages of 18 and 24; 24.3% were from 25 to 44; 21.9% were from 45 to 64; and 17.7% were 65 or older. The gender makeup of the city was 47.1% male and 52.9% female.
At the 2000 census there were 5,720 people, 2,256 households, and 1,534 families living in the city. The population density was 1,182.7 people per square mile. There were 2,417 housing units at an average density of 499.8/sq mi. The racial makeup of the city was 97.80% White, 0.19% African American, 0.42% Native American, 0.30% Asian, 0.12% from other races, and 1.17% from two or more races. Hispanic or Latino of any race were 1.75%. Of the 2,256 households 34.7% had children under the age of 18 living with them, 53.2% were married couples living together, 11.4% had a female householder with no husband present, and 32.0% were non-families. 28.7% of households were one person and 16.0% were one person aged 65 or older. The average household size was 2.44 and the average family size was 3.00. The age distribution was 27.1% under the age of 18, 9.4% from 18 to 24, 27.2% from 25 to 44, 18.2% from 45 to 64, and 18.1% 65 or older. The median age was 35 years. For every 100 females, there were 85.0 males. For every 100 females age 18 and over, there were 79.3 males. As of 2000, The median household income was $27,753, and the median family income was $36,090. Males had a median income of $27,813 versus $20,752 for females. The per capita income for the city was $14,855. About 5.5% of families and 11.6% of the population were below the poverty line, including 10.2% of those under age 18 and 12.2% of those age 65 or over.
