| Adair County | 19001 | Central | Greenfield, Stuart |
| Adams County | 19003 | Central | Corning |
| Allamakee County | 19005 | Central | Harpers Ferry, Postville, Waukon |
| Appanoose County | 19007 | Central | Centerville, Moravia |
| Audubon County | 19009 | Central | Audubon |
| Benton County | 19011 | Central | Belle Plaine, Blairstown, Norway, Urbana, Vinton, Walford |
| Black Hawk County | 19013 | Central | Cedar Falls, Hudson, Janesville, Jesup, Waterloo |
| Boone County | 19015 | Central | Boone, Madrid, Ogden |
| Bremer County | 19017 | Central | Janesville, Plainfield, Waverly |
| Buchanan County | 19019 | Central | Independence, Jesup, Rowley, Winthrop |
| Buena Vista County | 19021 | Central | Rembrandt, Storm Lake |
| Butler County | 19023 | Central | Greene, Shell Rock |
| Calhoun County | 19025 | Central | Lake City, Lohrville, Lytton, Manson, Rockwell City |
| Carroll County | 19027 | Central | Breda, Carroll, Coon Rapids, Manning, Ralston, Templeton |
| Cass County | 19029 | Central | Anita, Atlantic, Griswold |
| Cedar County | 19031 | Central | Clarence, Tipton, West Branch, Wilton |
| Cerro Gordo County | 19033 | Central | Clear Lake, Mason City, Nora Springs, Ventura |
| Cherokee County | 19035 | Central | Cherokee |
| Chickasaw County | 19037 | Central | Fredericksburg, Ionia, New Hampton |
| Clarke County | 19039 | Central | Murray, Osceola |
| Clay County | 19041 | Central | Spencer |
| Clayton County | 19043 | Central | Edgewood, Elkader, Luana, McGregor, Monona, Postville, St. Olaf, Strawberry Point |
| Clinton County | 19045 | Central | Camanche, Clinton, DeWitt, Maquoketa, Wheatland |
| Crawford County | 19047 | Central | Arion, Denison, Schleswig, Vail, Westside |
| Dallas County | 19049 | Central | Adel, Clive, Granger, Grimes, Perry, Redfield, Urbandale, Waukee, West Des Moines, Woodward |
| Davis County | 19051 | Central | Bloomfield |
| Decatur County | 19053 | Central | Decatur City, Van Wert |
| Delaware County | 19055 | Central | Delhi, Dyersville, Earlville, Edgewood, Hopkinton, Manchester, Masonville |
| Des Moines County | 19057 | Central | Burlington, Danville, Mediapolis, West Burlington, Yarmouth |
| Dickinson County | 19059 | Central | Arnolds Park, Lake Park, Milford, Spirit Lake |
| Dubuque County | 19061 | Central | Cascade, Dubuque, Dyersville, Farley, New Vienna, Peosta |
| Emmet County | 19063 | Central | Armstrong, Estherville, Ringsted |
| Fayette County | 19065 | Central | Arlington, Clermont, Fayette, Oelwein, West Union |
| Floyd County | 19067 | Central | Charles City, Nora Springs |
| Franklin County | 19069 | Central | Ackley, Alexander, Coulter, Hampton, Sheffield |
| Fremont County | 19071 | Central | Farragut, Hamburg, Shenandoah, Tabor |
| Greene County | 19073 | Central | Belmond, Jefferson, Paton, Ralston |
| Grundy County | 19075 | Central | Beaman, Conrad, Dike, Grundy Center, Reinbeck |
| Guthrie County | 19077 | Central | Coon Rapids, Stuart |
| Hamilton County | 19079 | Central | Blairsburg, Ellsworth, Jewell Junction, Webster City |
| Hancock County | 19081 | Central | Corwith, Forest City, Garner, Goodell, Kanawha |
| Hardin County | 19083 | Central | Ackley, Alden, Iowa Falls, New Providence, Union |
| Harrison County | 19085 | Central | Dunlap |
| Henry County | 19087 | Central | Mount Pleasant, New London |
| Howard County | 19089 | Central | Cresco |
| Humboldt County | 19091 | Central | Dakota City, Gilmore City, Humboldt |
| Ida County | 19093 | Central | Holstein, Ida Grove |
| Iowa County | 19095 | Central | Conroy, Marengo, Williamsburg |
| Jackson County | 19097 | Central | Maquoketa, Monmouth, Preston |
| Jasper County | 19099 | Central | Baxter, Kellogg, Lynnville, Mingo, Mitchellville, Monroe, Newton, Prairie City, Reasnor, Sully |
| Jefferson County | 19101 | Central | Fairfield |
| Johnson County | 19103 | Central | Coralville, Hills, Iowa City, North Liberty, Oxford, Swisher, West Branch |
| Jones County | 19105 | Central | Anamosa, Cascade, Monticello |
| Keokuk County | 19107 | Central | Keswick, Sigourney |
| Kossuth County | 19109 | Central | Algona, Bancroft, Fenton, West Bend |
| Lee County | 19111 | Central | Fort Madison, Franklin, Houghton, Keokuk |
| Linn County | 19113 | Central | Cedar Rapids, Coggon, Fairfax, Hiawatha, Lisbon, Marion, Mount Vernon, Springville, Troy Mills, Walford |
| Louisa County | 19115 | Central | Columbus Junction |
| Lucas County | 19117 | Central | Chariton |
| Lyon County | 19119 | Central | Doon, George, Inwood, Rock Rapids |
| Madison County | 19121 | Central | Bevington, Winterset |
| Mahaska County | 19123 | Central | Eddyville, Fremont, Oskaloosa |
| Marion County | 19125 | Central | Harvey, Knoxville, Melcher–Dallas, Pella |
| Marshall County | 19127 | Central | Albion, Marshalltown, Melbourne |
| Mills County | 19129 | Central | Emerson, Glenwood, Pacific Junction, Tabor |
| Mitchell County | 19131 | Central | Osage, St. Ansgar |
| Monroe County | 19135 | Central | Eddyville |
| Montgomery County | 19137 | Central | Red Oak |
| Muscatine County | 19139 | Central | Moscow, Muscatine, Walcott, West Liberty, Wilton |
| O’Brien County | 19141 | Central | Hartley, Sheldon |
| Osceola County | 19143 | Central | Sibley |
| Page County | 19145 | Central | Clarinda, Shenandoah |
| Palo Alto County | 19147 | Central | Emmetsburg, Graettinger, West Bend |
| Plymouth County | 19149 | Central | Le Mars, Remsen, Sioux City |
| Pocahontas County | 19151 | Central | Gilmore City, Laurens, Pocahontas |
| Polk County | 19153 | Central | Altoona, Ankeny, Bondurant, Clive, Des Moines, Elkhart, Granger, Grimes, Johnston, Mitchellville, Pleasant Hill, Urbandale, West Des Moines |
| Pottawattamie County | 19155 | Central | Avoca, Carter Lake, Council Bluffs, Crescent, Oakland, Shelby |
| Poweshiek County | 19157 | Central | Brooklyn, Grinnell, Malcom, Montezuma |
| Ringgold County | 19159 | Central | Mount Ayr, Redding |
| Sac County | 19161 | Central | Auburn, Lytton, Schaller, Wall Lake |
| Scott County | 19163 | Central | Bettendorf, Buffalo, Davenport, Eldridge, New Liberty, Princeton, Riverdale, Walcott |
| Shelby County | 19165 | Central | Defiance, Harlan, Portsmouth, Shelby |
| Sioux County | 19167 | Central | Boyden, Granville, Hawarden, Hospers, Hull, Ireton, Orange City, Rock Valley, Sheldon, Sioux Center |
| Story County | 19169 | Central | Ames, Colo, Huxley, Nevada, Story City, Zearing |
| Tama County | 19171 | Central | Dysart, Elberon, Tama |
| Taylor County | 19173 | Central | Lenox |
| Union County | 19175 | Central | Creston |
| Van Buren County | 19177 | Central | Bonaparte, Milton |
| Wapello County | 19179 | Central | Eddyville, Ottumwa |
| Warren County | 19181 | Central | Bevington, Des Moines, Indianola, New Virginia, West Des Moines |
| Washington County | 19183 | Central | Kalona, Riverside, Washington |
| Wayne County | 19185 | Central | Allerton, Corydon, Promise City, Seymour |
| Webster County | 19187 | Central | Fort Dodge, Harcourt, Vincent |
| Winnebago County | 19189 | Central | Forest City, Lake Mills, Leland |
| Winneshiek County | 19191 | Central | Decorah, Fort Atkinson |
| Woodbury County | 19193 | Central | Correctionville, Lawton, Sergeant Bluff, Sioux City |
| Worth County | 19195 | Central | Kensett, Northwood |
| Wright County | 19197 | Central | Belmond, Clarion, Eagle Grove, Goldfield |
