521
- 52101 Decorah
- 52132 Calmar
- 52133 Castalia
- 52134 Chester
- 52135 Clermont
- 52136 Cresco
- 52140 Dorchester
- 52141 Elgin
- 52142 Fayette
- 52144 Fort Atkinson
- 52146 Harpers Ferry
- 52147 Hawkeye
- 52151 Lansing
- 52154 Lawler
- 52155 Lime Springs
- 52156 Luana
- 52157 Mc Gregor
- 52158 Marquette
- 52159 Monona
- 52160 New Albin
- 52161 Ossian
- 52162 Postville
- 52163 Protivin
- 52164 Randalia
- 52165 Ridgeway
- 52166 Saint Lucas
- 52168 Spillville
- 52169 Wadena
- 52170 Waterville
- 52171 Waucoma
- 52172 Waukon
- 52175 West Union