| Place Name | Union (Rock County) |
| Place Type | Town |
| ZIP Code(s) | 53521 53536 53589 |
| County | Rock County |
| Area Code(s) | 608 |
| Timezone | Central Standard Time (CST) |
| Population (2021) | 1,987 |
| Majority Ethnicity | White 96.31% |
| Metro/Micro Stats Area | Janesville-Beloit, WI |
| US Congressional District(s) | Wisconsin 2nd |
| State Assembly Districts | 45 |
| State Senate Districts | 15 |
| Race/Ethnicy | Percentage of Population (2021) |
|---|---|
| White | 96.31% |
| African American | 0% |
| Hispanic | 0.1% |
| Asian | 0% |
| Native American | 0% |
| Hawaiin/Pacific Islander | 3.59% |