Founded on Jan 15, 1851, Sioux County is one of 99 counties in the state of Iowa. Historically, Sioux County was formed from Plymouth County. The city of Orange City is the county seat. With FIPS code of 167, Sioux County has a population of 35,893 and area of 768 square miles (1,989 km2).
List of all cities in Sioux County, IA alphabetically
| City/Town | Postal Code | Area Code |
| Alton, IA | 51003 | 712 |
| Boyden, IA | 51234 | 712 |
| Carmel, IA | 51247 | 712 |
| Carnes, IA | 51003 | 712 |
| Chatsworth, IA | 51011 | 712 |
| Granville, IA | 51022 | 712 |
| Hawarden, IA | 51011 | 712 |
| 51023 | 712 | |
| Hospers, IA | 51238 | 712 |
| Hull, IA | 51239 | 712 |
| Ireton, IA | 51027 | 712 |
| Lebanon, IA | 51250 | 712 |
| Matlock, IA | 51244 | 712 |
| Maurice, IA | 51036 | 712 |
| McNally, IA | 51027 | 712 |
| Middleburg, IA | 51041 | 712 |
| Newkirk, IA | 51238 | 712 |
| Orange City, IA | 51041 | 712 |
| Perkins, IA | 51239 | 712 |
| Rock Valley, IA | 51247 | 712 |
| Sioux Center, IA | 51250 | 712 |