State directory / South Dakota
US number directory / South Dakota
South Dakota
area codes
The earliest listed South Dakota code is 605, in service since 1947; the state now has 1 geographic code.
1geographic area code
in this reference
in this reference
Earliest listed605 · 1947
Standard timeCT / MT
Overlays in this stateNone recorded in this snapshot
Major city starting points
Pierre (capital): 605; Sioux Falls (largest city in state reference): 605.
| City | Reference role | Codes to check |
|---|---|---|
| Pierre | Capital | 605 |
| Sioux Falls | Largest city in state reference | 605 |
City reference · 2026-10-25
Codes, cities & coverage
NANPA lists no active overlay complex for South Dakota on 2026-10-25.
| Code | Region / major cities named in the reference | Introduced | Active overlay complexes |
|---|---|---|---|
| 605 | South Dakota (all) | 01-Jan-1947 | None active in NANPA snapshot |
NANPA dates & overlays · 2026-10-25
Wikipedia geography · 2026-10-25 · CC BY-SA 4.0
Time zones
South Dakota spans 2 standard-time offsets in the state reference: CT / MT.
| Standard offset | Region | Daylight saving |
|---|---|---|
| UTC−06:00 CT | Eastern half of state: UTC−06:00 CST Central Standard Time | Yes |
| UTC−07:00 MT | Western half of state: UTC−07:00 MST Mountain Standard Time | Yes |