Founded in 1825, Adams County is one of 102 counties in the state of Illinois. Historically, Adams County was formed from Pike County. The city of Quincy is the county seat. With FIPS code of 1, Adams County has a population of 64,954 and area of 855 square miles (2,214 km2).
List of all cities in Adams County, IL alphabetically
| City/Town | Postal Code | Area Code |
| Adams, IL | 62347 | 217 |
| Bigneck, IL | 62349 | 217 |
| Bluff Hall, IL | 62360 | 217 |
| Burton, IL | 62301 | 217 |
| Camp Point, IL | 62320 | 217 |
| Chestline, IL | 62347 | 217 |
| Clayton, IL | 62324 | 217 |
| Coatsburg, IL | 62325 | 217 |
| Columbus, IL | 62305 | 217 |
| 62320 | 217 | |
| Fall Creek, IL | 62360 | 217 |
| Fowler, IL | 62338 | 217 |
| Golden, IL | 62339 | 217 |
| Kellerville, IL | 62324 | 217 |
| La Prairie, IL | 62346 | 217 |
| Liberty, IL | 62347 | 217 |
| Lima, IL | 62348 | 217 |
| Loraine, IL | 62349 | 217 |
| Marblehead, IL | 62301 | 217 |
| Marcelline, IL | 62376 | 217 |
| Mendon, IL | 62351 | 217 |
| Paloma, IL | 62359 | 217 |
| Payson, IL | 62360 | 217 |
| Plainville, IL | 62365 | 217 |
| Quincy, IL | 62301 | 217 |
| 62305 | 217 | |
| 62306 | 217 | |
| Richfield, IL | 62365 | 217 |
| Tioga, IL | 62351 | 217 |
| Ursa, IL | 62376 | 217 |