605 Area Code: Location, Time Zone, Major Cities & Scam Alerts

The 605 area code is the single area code serving the entire state of South Dakota. Assigned in 1947 as one of the original area codes, 605 has covered all of the Mount Rushmore State on its own ever since, from Sioux Falls in the east to Rapid City and the Black Hills in the west.

Quick Summary of the 605 Area Code

Geographic Coverage

The 605 area code is a statewide code covering all of South Dakota, including the largest city of Sioux Falls and the college town of Brookings in the east, Aberdeen and Watertown in the northeast, Mitchell and Yankton in the south, the state capital of Pierre in the center, and Rapid City – the gateway to the Black Hills and Mount Rushmore – in the west. It borders North Dakota, Minnesota, Iowa, Nebraska, Wyoming, and Montana.

Time Zone

The 605 area code spans two time zones, split roughly along the Missouri River that runs through the middle of the state. Eastern South Dakota – including Sioux Falls, Brookings, Aberdeen, Watertown, and the capital Pierre – observes Central Time (CT), while western South Dakota – including Rapid City, the Black Hills, and the Badlands – observes Mountain Time (MT), one hour behind. Both zones follow daylight saving time from mid-March through early November, so when calling a 605 number it helps to know whether the person is in eastern (Central) or western (Mountain) South Dakota.

Tip: Business hours across the 605 region generally run 9:00 AM to 5:00 PM local time, Monday through Friday.

How to Dial a 605 Number

Area code 605 is not part of an overlay, and as the only area code in South Dakota it has traditionally allowed 7-digit local dialing within the state. However, 10-digit dialing is now the recommended nationwide standard, and dialing the full 10-digit number (605 + the seven-digit line number) always works reliably. For international callers, dial your country’s exit code, then +1 (the North American country code), then 605, followed by the seven-digit local number.

Scam Alerts for the 605 Area Code

Like every U.S. area code, 605 has been used by scammers who spoof local numbers to appear trustworthy. Residents across South Dakota should stay alert to the following common tactics:

If you receive a suspicious call from a 605 number, take these steps to protect yourself:

1. Do not share personal information such as Social Security numbers, bank details, or passwords over the phone.
2. Hang up and verify by calling the organization back using an official number from its website.
3. Report the call to the FTC at reportfraud.ftc.gov and to the South Dakota Attorney General’s Consumer Protection Division.
4. Block the number and consider registering with the National Do Not Call Registry.

Red Flag: Legitimate agencies such as the IRS, Social Security Administration, or your local utility company (Xcel Energy or Black Hills Energy) will never demand immediate payment by gift card, wire transfer, or cryptocurrency. Any 605 caller making such a demand is a scammer.

History and Economy of the 605 Region

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Area code 605 is one of the original 86 codes established in 1947, and a single code has always been enough for the sparsely populated state. The regional economy is anchored by agriculture – corn, soybeans, cattle, and wheat across the prairie – and by financial services in Sioux Falls, which became a national credit-card hub after South Dakota removed its interest-rate cap in the early 1980s and drew Citibank and others; the city is also home to the Sanford and Avera health systems. Tourism is a major force in the west, where Mount Rushmore, the Black Hills, Badlands National Park, Custer State Park, and the annual Sturgis Motorcycle Rally draw millions of visitors, while Ellsworth Air Force Base near Rapid City and South Dakota State University in Brookings add to the economy.

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Looking Up a 605 Number

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To identify a 605 caller, use a reverse phone lookup service or search the full 10-digit number online. Many South Dakota businesses, government offices, and healthcare providers list their 605 numbers publicly, so a quick search often confirms a legitimate caller. For unknown numbers, let the call go to voicemail – genuine callers usually leave a message.

Nearby & Related Area Codes

South Dakota is served by the single 605 area code, with no overlay. These neighboring area codes are worth knowing:

• 701 – Statewide North Dakota
• 308 – Central & Western Nebraska
• 712 – Western Iowa

You can also browse our full directory of South Dakota area codes for more regional guides.

↑ See the complete list of All US Area Codes by State – every area code across all 50 states in one directory.

Explore Neighboring States

Researching area codes just across the state line? Start with these codes in the states that border South Dakota:

• North Dakota – area code 701
• Minnesota – area code 612
• Iowa – area code 515
• Nebraska – area code 402
• Wyoming – area code 307
• Montana – area code 406

Frequently Asked Questions

Where is the 605 area code located?

The 605 area code covers the entire state of South Dakota, including Sioux Falls, Rapid City, Aberdeen, Brookings, Watertown, Mitchell, Pierre, and Yankton.

Does South Dakota have more than one area code?

No. South Dakota is served entirely by the single 605 area code, one of the few states covered by just one code with no overlay.

Do I need to dial 10 digits for 605?

As the only area code in South Dakota, 605 has historically allowed 7-digit local dialing, but dialing the full 10 digits is now the recommended standard and always works.

What time zone is the 605 area code in?

The 605 region is split: eastern South Dakota (including Sioux Falls) is on Central Time, while western South Dakota (including Rapid City and the Black Hills) is on Mountain Time.

Related 605 Guides

• Is a 605 call safe? Read Is area code 605 a scam? Spam & safety guide.
• Local coverage: see the Sioux Falls area code guide.
• Worried about spam or robocalls? Browse our Scam Alerts directory.