Area codes 419 and 567

The largest city served by these area codes is Toledo (and its suburbs of Holland, Maumee, Northwood, Oregon, Ottawa Hills, Perrysburg, Rossford, Sylvania, Swanton, Waterville, and Whitehouse).

The first nationwide telephone numbering plan of 1947 divided Ohio into four numbering plan areas (NPAs), roughly forming a quadrant layout for telecommunication services in the state.

Despite the presence of Toledo, the state's fourth-largest city, 419 had been the last of Ohio's original four numbering plan areas, and one of the few original NPAs not covering an entire state, that had never been split or overlaid.

[1][2] Other municipalities served by these area codes include Ada, Ashland, Bellevue, Bluffton, Bowling Green, Bryan, Bucyrus, Celina, Clyde, Crestline, Defiance, Delphos, Edgerton, Edison, Edon, Elmore, Findlay, Fostoria, Fremont, Galion, Genoa, Kenton, Lima, Mansfield, Montpelier, Mount Gilead, Napoleon, Norwalk, Oak Harbor, Port Clinton, Sandusky, Shelby, St. Marys, Tiffin, Upper Sandusky, Van Wert, Wapakoneta, Wauseon, Willard, and Woodville.

Other areas served include the Lake Erie Islands north of Port Clinton and west of Sandusky.