| Official Zip Code Name | Fairfax |
| Zip Code State | South Dakota |
| Primary County: | Gregory |
| Area Code | 605 |
| Current Population: | 37081 |
| Racial Majority: | White 62.49% |
| Median Household Income | $55618 |
| Average Adjusted Gross Income | $89060 |
| Time Zone: | 6 |
| Elevation Range | 1357 ft. |
| Area | 102.753 Sqm. |
| Coordinates(Y,X) | 43.076756, -98.720646 |