Founded on Jan 15, 1851, Union County is one of 99 counties in the state of Iowa. Historically, Union County was formed from Clarke County. The city of Creston is the county seat. With FIPS code of 175, Union County has a population of 12,018 and area of 424 square miles (1,098 km2).
List of all cities in Union County, IA alphabetically
| City/Town | Postal Code | Area Code |
| Afton, IA | 50830 | 641 |
| Arispe, IA | 50831 | 641 |
| Barney, IA | 50149 | 641 |
| Creston, IA | 50801 | 641 |
| Cromwell, IA | 50842 | 641 |
| Lorimor, IA | 50149 | 641 |
| Shannon City, IA | 50861 | 641 |
| Talmage, IA | 50254 | 641 |
| Thayer, IA | 50254 | 641 |