| Official Name: | Vienna Township |
| Settlement Type: | Township |
| Image Map1: | Map of Illinois highlighting Grundy County.svg |
| Mapsize1: | 150px |
| Map Caption1: | Grundy County's location in Illinois |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Illinois |
| Subdivision Type2: | County |
| Subdivision Name2: | Grundy |
| Established Title: | Established |
| Established Date: | November 6, 1849 |
| Area Total Sq Mi: | 35.72 |
| Area Land Sq Mi: | 35.69 |
| Area Water Sq Mi: | 0.02 |
| Area Water Percent: | 0.06 |
| Population As Of: | 2020 |
| Population Total: | 666 |
| Population Density Sq Mi: | auto |
| Elevation M: | 195 |
| Elevation Ft: | 640 |
| Coordinates: | 41.2447°N -88.5319°W |
| Timezone: | CST |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Postal Code Type: | ZIP codes |
| Postal Code: | 60437, 60444, 60450, 60479, 61360 |
| Blank Name: | FIPS code |
| Blank Info: | 17-063-77850 |
| Unit Pref: | Imperial |
Vienna Township is one of seventeen townships in Grundy County, Illinois, USA. As of the 2020 census, its population was 666 and it contained 267 housing units.[1]
According to the 2021 census gazetteer files, Vienna Township has a total area of 35.72sqmi, of which 35.69sqmi (or 99.94%) is land and 0.02sqmi (or 0.06%) is water.[2]
(This list is based on USGS data and may include former settlements.)
As of the 2020 census there were 666 people, 375 households, and 232 families residing in the township. The population density was 18.65PD/sqmi. There were 267 housing units at an average density of 7.48/sqmi. The racial makeup of the township was 91.29% White, 0.00% African American, 0.45% Native American, 1.35% Asian, 0.00% Pacific Islander, 3.15% from other races, and 3.75% from two or more races. Hispanic or Latino of any race were 7.06% of the population.
There were 375 households, out of which 23.70% had children under the age of 18 living with them, 44.27% were married couples living together, 12.27% had a female householder with no spouse present, and 38.13% were non-families. 37.30% of all households were made up of individuals, and 5.90% had someone living alone who was 65 years of age or older. The average household size was 2.55 and the average family size was 3.41.
The township's age distribution consisted of 28.4% under the age of 18, 9.2% from 18 to 24, 29.6% from 25 to 44, 24.3% from 45 to 64, and 8.6% who were 65 years of age or older. The median age was 38.2 years. For every 100 females, there were 106.7 males. For every 100 females age 18 and over, there were 117.1 males.
The median income for a household in the township was $87,917, and the median income for a family was $102,625. Males had a median income of $61,641 versus $23,558 for females. The per capita income for the township was $30,388. About 11.2% of families and 14.3% of the population were below the poverty line, including 28.0% of those under age 18 and 6.1% of those age 65 or over.