2020 census
As of the 2020 census, the county had a population of 42,980. The median age was 37.9 years. 25.1% of residents were under the age of 18 and 17.2% of residents were 65 years of age or older. For every 100 females there were 99.4 males, and for every 100 females age 18 and over there were 96.2 males age 18 and over. [11]
The racial makeup of the county was 82.6% White, 3.2% Black or African American, 0.6% American Indian and Alaska Native, 0.7% Asian, 0.3% Native Hawaiian and Pacific Islander, 5.0% from some other race, and 7.6% from two or more races. Hispanic or Latino residents of any race comprised 9.3% of the population. [12]
Pettis County, Missouri – Racial and ethnic composition
Note: the US Census treats Hispanic/Latino as an ethnic category. This table excludes Latinos from the racial categories and assigns them to a separate category. Hispanics/Latinos may be of any race.| Race / Ethnicity (NH = Non-Hispanic) | Pop 1980 [13] | Pop 1990 [14] | Pop 2000 [15] | Pop 2010 [16] | Pop 2020 [17] | % 1980 | % 1990 | % 2000 | % 2010 | % 2020 |
|---|
| White alone (NH) | 34,591 | 33,781 | 35,810 | 36,701 | 34,751 | 95.09% | 95.33% | 90.88% | 86.97% | 80.85% |
| Black or African American alone (NH) | 1,374 | 1,164 | 1,181 | 1,244 | 1,353 | 3.78% | 3.28% | 3.00% | 2.95% | 3.15% |
| Native American or Alaska Native alone (NH) | 87 | 96 | 130 | 137 | 159 | 0.24% | 0.27% | 0.33% | 0.32% | 0.37% |
| Asian alone (NH) | 88 | 114 | 154 | 247 | 294 | 0.24% | 0.32% | 0.39% | 0.59% | 0.68% |
| Native Hawaiian or Pacific Islander alone (NH) | x [18] | x [19] | 18 | 30 | 120 | x | x | 0.05% | 0.07% | 0.28% |
| Other race alone (NH) | 15 | 14 | 45 | 41 | 119 | 0.04% | 0.04% | 0.11% | 0.10% | 0.28% |
| Mixed race or Multiracial (NH) | x [20] | x [21] | 538 | 755 | 2,168 | x | x | 1.37% | 1.79% | 5.04% |
| Hispanic or Latino (any race) | 223 | 268 | 1,527 | 3,046 | 4,016 | 0.61% | 0.76% | 3.88% | 7.22% | 9.34% |
| Total | 36,378 | 35,437 | 39,403 | 42,201 | 42,980 | 100.00% | 100.00% | 100.00% | 100.00% | 100.00% |
60.6% of residents lived in urban areas, while 39.4% lived in rural areas. [22]
There were 16,588 households in the county, of which 31.5% had children under the age of 18 living with them and 25.9% had a female householder with no spouse or partner present. About 29.0% of all households were made up of individuals and 13.1% had someone living alone who was 65 years of age or older. [11]
There were 18,563 housing units, of which 10.6% were vacant. Among occupied housing units, 67.2% were owner-occupied and 32.8% were renter-occupied. The homeowner vacancy rate was 2.1% and the rental vacancy rate was 10.4%. [11]
2000 census
Per the 2000 census, [23] there were 39,403 people, 15,568 households, and 10,570 families residing in the county. The population density was 58 people per square mile (22 people/km2). There were 16,963 housing units at an average density of 25 units per square mile (9.7/km2). The racial makeup of the county was 92.06% White, 3.04% Black or African American, 0.38% Native American, 0.39% Asian, 0.05% Pacific Islander, 2.46% from other races, and 1.62% from two or more races. Approximately 3.88% of the population were Hispanic or Latino of any race.
There were 15,568 households, out of which 32.50% had children under the age of 18 living with them, 53.30% were married couples living together, 10.50% had a female householder with no husband present, and 32.10% were non-families. 27.00% of all households were made up of individuals, and 11.70% had someone living alone who was 65 years of age or older. The average household size was 2.49 and the average family size was 3.01.
In the county, the population was spread out, with 26.30% under the age of 18, 9.30% from 18 to 24, 27.90% from 25 to 44, 21.10% from 45 to 64, and 15.40% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 94.40 males. For every 100 females age 18 and over, there were 91.70 males.
The median income for a household in the county was $31,822, and the median income for a family was $38,073. Males had a median income of $29,221 versus $19,554 for females. The per capita income for the county was $16,251. About 10.20% of families and 12.80% of the population were below the poverty line, including 16.60% of those under age 18 and 10.50% of those age 65 or over.
United States
Missouri 
