641 Area Code – Mason City, Iowa: Location, Time Zone & History

Area code 641 was created in 2000 when it split away from the eastern and southern portions of area code 515's original territory, becoming effective July 9, 2000. It marked Iowa's first area code split since the state's original numbering plan was established in 1947, and after a five-month permissive-dialing period, mandatory use of 641 began on December 3, 2000.

The territory covers south-central and north-central Iowa, centered on Mason City and reaching Marshalltown, Ottumwa, Fairfield, Newton, Oskaloosa, and Tama. Unlike many U.S. regions facing similar growth pressures, Iowa has never adopted an area-code overlay; each of its five numbering plan areas, including 641, still covers its own distinct, non-overlapping territory.

The regional economy leans heavily on agriculture and food processing. The JBS USA pork plant in Marshalltown, operating since 1880 and acquired by JBS in 2007, ranks as the third-largest pork processing facility in the country and remains the city's largest employer, while a sister JBS plant in Ottumwa supports more than 160 local livestock producers. Manufacturing also has deep roots here, with firms such as Sukup Manufacturing, Curries, and Fisher Controls/Emerson based in Marshalltown, alongside healthcare anchored by MercyOne North Iowa Medical Center in Mason City.