Founded in 1855, Osage County is one of 105 counties in the state of Kansas. Historically, Osage County was one of the original 36 counties (Formerly Weller County). The city of Lyndon is the county seat. With FIPS code of 139, Osage County has a population of 15,768 and area of 704 square miles (1,823 km2).
List of all cities in Osage County, KS alphabetically
| City/Town | Postal Code | Area Code |
| Burlingame, KS | 66413 | 785 |
| Carbondale, KS | 66414 | 785 |
| Lyndon, KS | 66451 | 785 |
| Melvern, KS | 66510 | 785 |
| Osage City, KS | 66523 | 785 |
| Overbrook, KS | 66524 | 785 |
| Quenemo, KS | 66528 | 785 |
| Scranton, KS | 66537 | 785 |
| Vassar, KS | 66543 | 785 |