Area Code 605 — Sioux Falls, South Dakota

NANP area code

605

UTC−6, UTC−5 during daylight saving

State
South Dakota
Primary city
Sioux Falls
Time zone
Central
In service
1947

The code reaches 363 communities and 66 counties across South Dakota.

Was this call legitimate?

The area code itself carries no risk signal. 605 is assigned to Sioux Falls, South Dakota, so a call from it is consistent with a real caller in that area — but the digits alone prove nothing, because they can be forged.

Caller ID is set by whoever places the call, not verified by the network. That is why neighbour spoofing works: an operation anywhere in the world can display a number that matches the area code — and often the first three digits after it — of the person being called, so the call looks local. Every community in the 605 territory is a plausible-looking origin for a forged 605 number, which is why one can be made to look like a neighbour to so many people.

If you did not recognise the call: let it go to voicemail — a legitimate caller with real business will leave one. Do not return the call using the number shown; look the organisation up independently and call the number you found. Never confirm personal details, card numbers, or one-time codes to someone who called you, however plausible the number looked.

Codes.zone publishes no complaint counts, risk scores, or caller identities. We hold no data on individual numbers and will not estimate what we cannot source.

Local time and when to call back

Time there now

Central · UTC−6, UTC−5 during daylight saving

Reasonable callback window

8:00 AM – 9:00 PM

local time in Central

Federal rules bar telemarketing calls to a residence outside 8:00 AM–9:00 PM in the called party's own time zone. It is a sensible bound for a personal callback too — and a caller who rang you well outside it was not observing it.

Overlay codes

605 is the only area code serving its territory — it has no overlay in the current numbering plan for South Dakota. Where a region has no overlay, a number's area code still corresponds to a single geographic area.

Cities served

largest 20 by ZIP count
Communities served by area code 605, ranked by how many ZIP codes each holds.
CityZIP codesCounty
Sioux Falls15Minnehaha County
Rapid City4Pennington County
Aberdeen2Brown County
Brookings2Brookings County
Chamberlain2Brule County
Huron2Beadle County
Spearfish2Lawrence County
Agar1Sully County
Akaska1Walworth County
Alcester1Union County
Alexandria1Hanson County
Allen1Bennett County
Alpena1Jerauld County
Amherst1Marshall County
Andover1Day County
Arlington1Kingsbury County
Armour1Douglas County
Artesian1Sanborn County
Ashton1Spink County
Astoria1Deuel County

343 further communities not listed. All South Dakota area codes →

Each point is a community served by 605, plotted from its record coordinates. The outline is the convex envelope of those points — a footprint, not a boundary.
  • Reference points and footprint
  • Not an official NANPA boundary
  • Not a USPS delivery area

Scope every community matched to 605. Source geoinfo-dataset (full_dataset) ZIP→NPA (2018 snapshot), GeoNames US postal codes (2026-07 postal dump) and Census 2024 county Gazetteer (2024 Gazetteer). Updated . Coordinates are place reference points, not boundaries.

Counties

Prefixes inside 605

We do not publish the NXX prefixes inside 605. The assignment of prefixes to rate centres comes from LERG routing data, which is proprietary, and we will not estimate it from postal data — ZIP codes and telephone prefixes do not map onto each other. Awaiting a clean-rights NPA-NXX source.