Significant events for area code 314
| Date |
Details |
| 1947 | One of the two original area codes for Missouri, covering the eastern area |
| January 7, 1996 | Area code 314 was split with 573 covering all of the area outside of the greater St. Louis area |
| May 22, 1999 | Area code 314 was split with 636 covering the western area of 314 |
| August 12, 2022 | Area code 314 was overlaid with 557. |