| Official Zip Code Name | Cortland |
| Zip Code State | Illinois |
| Primary County: | Dekalb |
| Area Code | 815/779 |
| Current Population: | 37081 |
| Racial Majority: | White 62.49% |
| Median Household Income | $55618 |
| Average Adjusted Gross Income | $89060 |
| Time Zone: | 6 |
| Elevation Range | 901 ft. |
| Area | 3.655 Sqm. |
| Coordinates(Y,X) | 41.925813, -88.690810 |