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South Dakota · United States

Area code 605: where it is and who calls from it

  • Spans Central and Mountain time

Reviewed by Sujan ThapaliyaLast updated

What is area code 605?

Area code 605 serves South Dakota, United States. It is in the Spans Central and Mountain time time zone.
Where area code 605 sits in a North American number: the three-digit area code, then the three-digit exchange code, then the four-digit line number, all under country code 1. The diagram also shows the two validity rules — an area code never starts with 0 or 1, and a repeated middle digit marks a service code such as 800 for toll-free rather than a place.
The 1 you dial before a ten-digit number is a long-distance prefix, not part of the number itself.

Area code 605

Type
Geographic area code
State / province
South Dakota
Country
United States
Time zone
Spans Central and Mountain time
In service since
1947

Step by step

How to call a 605 number

The same ten digits, dialled three different ways depending on where you are calling from.

  1. 1

    Within the same area code

    Many carriers still allow seven digits inside 605, but overlays have made ten-digit dialling the safe default. Dial 605 followed by the seven-digit number.
  2. 2

    From elsewhere in the US or Canada

    Dial 1, then 605, then the seven-digit number — eleven digits in total. The leading 1 is the North American long-distance prefix, not part of the number.
  3. 3

    From outside North America

    Dial your country's exit code, then 1 for the North American Numbering Plan, then 605, then the seven-digit number. On a mobile, type + instead of the exit code: +1 605 followed by the number works from any country.

Background

About 605

605 covers South Dakota with no overlay code sharing its territory, so the code still maps cleanly to one place — which is what makes it recognisable on caller ID. It is one of the original 1947 area codes, assigned when the numbering plan was first drawn up, which is why it reads as familiar rather than suspicious to most recipients.

Unwanted calls

Why you are getting 605 calls

The reason an unfamiliar 605 number keeps calling is usually neighbour spoofing: automated systems fake a caller ID in the recipient’s own area code because a local-looking number is answered far more often than an unfamiliar one. The number displayed is frequently not the number placing the call, and may belong to someone with no idea it is being used.

What actually helps:

  • Let unknown numbers go to voicemail. Automated diallers rarely leave a message; a real caller will.
  • Do not press any key to be removed. On an automated call, a keypress confirms a live human and increases the volume you get.
  • Register on the national Do Not Call list and report unwanted calls. It does not stop fraud, but it does constrain legitimate telemarketers.
  • Turn on your carrier’s call-filtering service. Filtering now uses STIR/SHAKEN attestation, which is why properly signed business calls get through and spoofed ones increasingly do not.

If it is your 605 business number being labelled as spam, the cause is different and fixable: unregistered caller ID name, low attestation, or a volume pattern carriers read as automated. Owning your numbers, registering CNAM and signing at Attestation A is what resolves it.

If you are calling into 605 rather than receiving from it, the relevant reading is how caller ID and attestation decide whether a call is answered — the same signals that decide whether a call from this code gets answered decide whether yours does.

Frequently asked questions

Where is area code 605?
Area code 605 covers South Dakota, United States.
Is a call from 605 a scam?
Not inherently. 605 is a legitimate area code serving real people and businesses in South Dakota. But spam callers frequently spoof caller ID to display a number in your own area code, a technique called neighbour spoofing. If you do not recognise the number, let it go to voicemail; a genuine caller will leave a message.
What time zone is 605 in?
605 is in the Spans Central and Mountain time time zone. Check the local time before calling back so you are inside normal business hours.
Can I get a 605 phone number?
Yes. Local numbers in 605 can be provisioned in minutes and used for calls, texts, and as your outbound caller ID. A number in the area code you are calling is answered noticeably more often than an out-of-state one.

Sources

  1. North American Numbering Plan Administrator — NANPAArea code assignments, relief planning, and which codes are in service across the North American Numbering Plan.
  2. ITU-T Recommendation E.164 — The international public telecommunication numbering plan — International Telecommunication UnionThe international number format, the 15-digit maximum, and how country codes and national numbers compose.

Get a 605 number for your business

A local 605 number, owned by you, with your business name on the caller ID and callbacks routed straight to your team. People answer local numbers, and they answer branded ones far more often still.

  • Branded caller ID (CNAM)
  • STIR/SHAKEN Attestation A
  • No subscription
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