Area code 605

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The map above is clickable; click on an area code to go to the page for that code. South Dakota's area code in blue with border states shown in yellow, orange and green

Area code 605 is the telephone area code in the North American Numbering Plan for the entire U.S. state of South Dakota. The numbering plan area was designated in 1947, when the American Telephone and Telegraph Company (AT&T) devised a comprehensive telephone numbering plan for the United States and Canada.

Before October 2021, area code 605 had telephone numbers assigned for the central office code 988. In 2020, 988 was designated nationwide as a dialing code for the National Suicide Prevention Lifeline, which created a conflict for exchanges that permit seven-digit dialing. Area code 605 was therefore scheduled to transition to ten-digit dialing by October 24, 2021.[1] Current projections suggest that South Dakota will require a second area code by late 2026, as the existing 605 area code is nearing exhaustion.[2]

  1. ^ "Transition to 10-digit dialing (for 988 as 3-digit access to National Suicide Prevention Hotline)" (PDF). North American Numbering Plan Administrator. January 8, 2021. Retrieved March 9, 2021.
  2. ^ 2023-1 NRUF and NPA Exhaust Analysis (PDF) (Report). East Brunswick, New Jersey: North American Numbering Plan Administrator. April 2023. p. 2. Retrieved June 30, 2023.