Founded in 1867, Sumner County is one of 105 counties in the state of Kansas. Historically, Sumner County was formed from Butler County. The city of Wellington is the county seat. With FIPS code of 191, Sumner County has a population of 22,385 and area of 1,182 square miles (3,061 km2).
List of all cities in Sumner County, KS alphabetically
| City/Town | Postal Code | Area Code |
| Argonia, KS | 67004 | 620 |
| Ashton, KS | 67051 | 620 |
| Belle Plaine, KS | 67013 | 620 |
| Caldwell, KS | 67022 | 620 |
| Conway Springs, KS | 67031 | 620 |
| Corbin, KS | 67022 | 620 |
| Geuda Springs, KS | 67051 | 620 |
| Hunnewell, KS | 67140 | 620 |
| Mayfield, KS | 67103 | 620 |
| Milan, KS | 67105 | 620 |
| Milton, KS | 67106 | 620 |
| Oxford, KS | 67119 | 620 |
| Peck, KS | 67120 | 316 |
| Riverdale, KS | 67152 | 620 |
| Sieboldt, KS | 67119 | 620 |
| South Haven, KS | 67140 | 620 |
| Wellington, KS | 67152 | 620 |