North American Numbers Source-cited · ownership disclosed
Area code
605
In service
United States · since 1947

South Dakota (statewide)

Area code 605 is the sole area code for the entire state of South Dakota, an original 1947 code with no split or overlay history.

The essentials Numbering data · NumberResearch · as of 2026-09-18
Place
South Dakota (statewide)
Type
geographic
Status
in service
In service since
1947
Projected exhaust
2034 Q3

Status, dates and counts are read from NumberResearch (NANPA / CNAC / FCC records). Assignment records show initial assignees, not the carrier serving a number today.

A · Where it is

Where 605 is

The entire state of South Dakota..

Communities served wholly or partly by 605:

Sioux FallsRapid CityAberdeenBrookingsWatertownPierre
B · Relationships

How it relates to other codes

The codes 605 was split from, spawned, or shares its area with. A split divides the map and changes some numbers; an overlay shares the same ground and changes none — what's the difference?

What's changing. No overlay. Single statewide code. Relief extended to roughly 2033 (re-check NANPA).
C · History

How 605 got here

1947
Designated as one of the original North American area codes.
Source: Wikipedia
2021-10
Transitioned to 10-digit dialing due to the 988 designation.
Source: Wikipedia
D · Capacity

How full it is

Prefixes assigned
759
Prefixes available
41
Thousands-blocks assigned
1,945

Prefix-assignment counts describe allocation to carriers, not how many individual numbers are in use. Full technical records: NumberResearch ↗.

Compare 605 with another code →
Sources
Wikipedia ↗
Area code 605
NumberResearch.org ↗
Live status, dates, assignment counts and exhaust forecast — data as of 2026-09-18 (CC BY 4.0).

Place, relationships and history above are compiled by North American Numbers from the sources listed and last checked 2026-09-18. A check date is not an expert review — see how this is made. Flag an error.