Area codes 608 and 353

Area codes 608 and 353 are telephone area codes in the North American Numbering Plan for much of southwestern Wisconsin, including the state capital city Madison. Area code 608 was assigned in 1955 to a numbering plan area created from areas with area code 414 and area code 715, and was the third area code created in Wisconsin. Rapid growth of the area, specifically in Dane County, brought the area code close to exhaustion of central office prefixes, with NANPA projections in 2022 projecting the need for relief by late 2023. In September 2022, the Wisconsin Public Service Commission and North American Numbering Plan Administrator (NANPA) announced an overlay complex for the numbering plan area with new area code 353, with an in-service date of September 15, 2023. New central office code orders were accepted starting on July 11, 2023, but activatlon is contingent on complete exhaustion of central office codes for 608.

Service area
The counties served by the area codes are Adams, Buffalo, Columbia, Crawford, Dane, Grant, Green, Iowa, Jackson, Juneau, La Crosse, Lafayette, Marquette, Monroe, Richland, Rock, Sauk, Trempealeau, and Vernon.

Cities in the numbering plan area are Madison, Waunakee, Mount Horeb, Verona, Sun Prairie, Monroe, Platteville, Lancaster, Lodi, Portage, Baraboo, Wisconsin Dells, Beloit, Janesville, La Crosse, Prairie du Chien, Prairie du Sac, Sauk City, Viroqua, and Sparta.

Ten-digit dialing
Prior to October 2021, area code 608 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. This area code was therefore scheduled to transition to ten-digit dialing by October 24, 2021. That allowed the 353 overlay to be implemented without permissive dialing period.