Area code 605

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.

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] The numbering plan area includes the following communities, which are serviced by the listed central office prefixes.

Area code 406 Area code 701 Area code 320 Area code 218 Area code 507 Area code 712 Area code 402 Area code 308 Area code 307
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