Founded on November 2, 1829, Union County is one of 75 counties in the state of Arkansas. Historically, Union County was formed from Clark and Hempstead counties. The city of El Dorado is the county seat. With FIPS code of 139, Union County has a population of 38,340 and area of 1,055.27 square miles (2,733 km2).
List of all cities in Union County, AR alphabetically
| City/Town | Postal Code | Area Code |
| Calion, AR | 71724 | 870 |
| El Dorado, AR | 71730 | 870 |
| 71731 | 870 | |
| 71768 | 870 | |
| Huttig, AR | 71747 | 870 |
| Junction City, AR | 71749 | 870 |
| Lawson, AR | 71750 | 870 |
| Mount Holly, AR | 71758 | 870 |
| Norphlet, AR | 71759 | 870 |
| Smackover, AR | 71762 | 870 |
| Strong, AR | 71765 | 870 |
| Urbana, AR | 71768 | 870 |
Map of Cities in Union County, AR
