501
- 50101 Galt
- 50102 Garden City
- 50103 Garden Grove
- 50104 Gibson
- 50105 Gilbert
- 50106 Gilman
- 50107 Grand Junction
- 50108 Grand River
- 50109 Granger
- 50111 Grimes
- 50112 Grinnell
- 50115 Guthrie Center
- 50116 Hamilton
- 50117 Hamlin
- 50118 Hartford
- 50119 Harvey
- 50120 Haverhill
- 50122 Hubbard
- 50123 Humeston
- 50124 Huxley
- 50125 Indianola
- 50126 Iowa Falls
- 50127 Ira
- 50128 Jamaica
- 50129 Jefferson
- 50130 Jewell
- 50131 Johnston
- 50132 Kamrar
- 50133 Kellerton
- 50134 Kelley
- 50135 Kellogg
- 50136 Keswick
- 50138 Knoxville
- 50139 Lacona
- 50140 Lamoni
- 50141 Laurel
- 50142 Le Grand
- 50143 Leighton
- 50144 Leon
- 50146 Linden
- 50147 Lineville
- 50148 Liscomb
- 50149 Lorimor
- 50150 Lovilia
- 50151 Lucas
- 50153 Lynnville
- 50154 Mc Callsburg
- 50155 Macksburg
- 50156 Madrid
- 50157 Malcom
- 50158 Marshalltown
- 50160 Martensdale
- 50161 Maxwell
- 50162 Melbourne
- 50163 Melcher Dallas
- 50164 Menlo
- 50165 Millerton
- 50166 Milo
- 50167 Minburn
- 50168 Mingo
- 50169 Mitchellville
- 50170 Monroe
- 50171 Montezuma
- 50173 Montour
- 50174 Murray