Area codes 309 and 861

The numbering plan area includes cities such as Bloomington, Canton, East Moline, East Peoria, Galesburg, Geneseo, Kewanee, Macomb, Minonk, Moline, Morton, Normal, Pekin, Peoria, Rock Island, Silvis, and many smaller communities in west-central Illinois.

861 was added to the numbering plan area on February 24, 2023, in formation of an overlay.

When the American Telephone and Telegraph Company created the first nationwide telephone numbering plan for Operator Toll Dialing in 1947, the state of Illinois was divided into four numbering plan areas (NPAs), generally laid out as a southern, central, and northern area, and a region around the city of Chicago.

Sometime after September 1956,[1] the 815 numbering plan area was divided roughly in half along a north-westerly to south-easterly running line, assigning area code 309 to its western part.

[3] For mitigation, a new all-services distributed overlay was announced with the new area code 861,[4] which commenced operation on February 24, 2023.