Founded in 1855, Johnson County is one of 105 counties in the state of Kansas. Historically, Johnson County was one of the original 36 counties. The city of Olathe is the county seat. With FIPS code of 91, Johnson County has a population of 613,219 and area of 477 square miles (1,235 km2).
List of all cities in Johnson County, KS alphabetically
| City/Town | Postal Code | Area Code |
| Clearview City, KS | 66019 | 913 |
| Countryside, KS | 66202 | 913 |
| De Soto, KS | 66018 | 913 |
| 66019 | 913 | |
| Edgerton, KS | 66021 | 913 |
| Fairway, KS | 66205 | 913 |
| Gardner, KS | 66030 | 913 |
| J C Penney Co, KS | 66250 | 913 |
| 66276 | 913 | |
| Lake Quivira, KS | 66217 | 913 |
| Leawood, KS | 66206 | 913 |
| 66207 | 913 | |
| 66209 | 913 | |
| 66211 | 913 | |
| 66224 | 913 | |
| Lenexa, KS | 66062 | 913 |
| 66210 | 913 | |
| 66213 | 913 | |
| 66214 | 913 | |
| 66215 | 913 | |
| 66216 | 913 | |
| 66217 | 913 | |
| 66219 | 913 | |
| 66220 | 913 | |
| 66227 | 913 | |
| 66251 | 913 | |
| 66285 | 913 | |
| 66286 | 913 | |
| Merriam, KS | 66202 | 913 |
| 66203 | 913 | |
| 66204 | 913 | |
| Mission, KS | 66201 | 913 |
| 66202 | 913 | |
| 66205 | 913 | |
| 66222 | 913 | |
| Mission Hills, KS | 66208 | 913 |
| Mission Woods, KS | 66205 | 913 |
| New Century, KS | 66031 | 913 |
| Olathe, KS | 66051 | 913 |
| 66061 | 913 | |
| 66062 | 913 | |
| 66063 | 913 | |
| Overland, KS | 66202 | 913 |
| 66203 | 913 | |
| 66204 | 913 | |
| 66206 | 913 | |
| 66207 | 913 | |
| 66208 | 913 | |
| 66209 | 913 | |
| 66210 | 913 | |
| 66211 | 913 | |
| 66212 | 913 | |
| 66213 | 913 | |
| 66214 | 913 | |
| 66215 | 913 | |
| 66221 | 913 | |
| 66223 | 913 | |
| 66224 | 913 | |
| 66225 | 913 | |
| 66282 | 913 | |
| Overland Park, KS | 66062 | 913 |
| 66085 | 913 | |
| 66201 | 913 | |
| 66202 | 913 | |
| 66203 | 913 | |
| 66204 | 913 | |
| 66206 | 913 | |
| 66207 | 913 | |
| 66208 | 913 | |
| 66209 | 913 | |
| 66210 | 913 | |
| 66211 | 913 | |
| 66212 | 913 | |
| 66213 | 913 | |
| 66214 | 913 | |
| 66215 | 913 | |
| 66221 | 913 | |
| 66223 | 913 | |
| 66224 | 913 | |
| 66225 | 913 | |
| 66251 | 913 | |
| 66282 | 913 | |
| 66283 | 913 | |
| Prairie Village, KS | 66202 | 913 |
| 66204 | 913 | |
| 66206 | 913 | |
| 66207 | 913 | |
| 66208 | 913 | |
| Quivira, KS | 66217 | 913 |
| Roeland Park, KS | 66205 | 913 |
| Shawnee, KS | 66203 | 913 |
| 66214 | 913 | |
| 66216 | 913 | |
| 66217 | 913 | |
| 66218 | 913 | |
| 66219 | 913 | |
| 66220 | 913 | |
| 66226 | 913 | |
| 66227 | 913 | |
| 66286 | 913 | |
| Shawnee Mission, KS | 66201 | 913 |
| 66202 | 913 | |
| 66203 | 913 | |
| 66204 | 913 | |
| 66205 | 913 | |
| 66206 | 913 | |
| 66207 | 913 | |
| 66208 | 913 | |
| 66209 | 913 | |
| 66210 | 913 | |
| 66211 | 913 | |
| 66212 | 913 | |
| 66213 | 913 | |
| 66214 | 913 | |
| 66215 | 913 | |
| 66216 | 913 | |
| 66217 | 913 | |
| 66218 | 913 | |
| 66219 | 913 | |
| 66220 | 913 | |
| 66221 | 913 | |
| 66222 | 913 | |
| 66223 | 913 | |
| 66224 | 913 | |
| 66225 | 913 | |
| 66226 | 913 | |
| 66227 | 913 | |
| 66250 | 913 | |
| 66251 | 913 | |
| 66276 | 913 | |
| 66282 | 913 | |
| 66283 | 913 | |
| 66285 | 913 | |
| 66286 | 913 | |
| Spring Hill, KS | 66083 | 913 |
| Sprint Corporation, KS | 66251 | 913 |
| Stanley, KS | 66221 | 913 |
| 66223 | 913 | |
| 66224 | 913 | |
| 66283 | 913 | |
| Stilwell, KS | 66085 | 913 |
| Westwood, KS | 66205 | 913 |
| Westwood Hills, KS | 66205 | 913 |