- Calamus
- California Junction
- Callender
- Calmar
- Calumet
- Camanche
- Cambridge
- Cantril
- Carbon
- Carlisle
- Carpenter
- Carroll
- Carson
- Carter Lake
- Cascade
- Casey
- Castalia
- Castana
- Cedar Falls
- Cedar Rapids
- Center Junction
- Center Point
- Centerville
- Centerville
- Central City
- Centralia
- Chapin
- Chariton
- Charles City
- Charlotte
- Charter Oak
- Chatsworth
- Chelsea
- Cherokee
- Chester
- Chillicothe
- Churdan
- Cincinnati
- Clare
- Clarence
- Clarinda
- Clarion
- Clarksville
- Clayton
- Clear Lake
- Clearfield
- Cleghorn
- Clemons
- Clermont
- Climbing Hill
- Clinton
- Clio
- Clive
- Clutier
- Coalville
- Coburg
- Coggon
- Coin
- Colesburg
- Colfax
- College Springs
- Collins
- Colo
- Columbus City
- Columbus Junction
- Colwell
- Conesville
- Conrad
- Conroy
- Conway
- Coon Rapids
- Coppock
- Coralville
- Corley
- Corning
- Correctionville
- Corwith
- Corydon
- Cotter
- Coulter
- Council Bluffs
- Craig
- Crawfordsville
- Crescent
- Cresco
- Creston
- Cromwell
- Crystal Lake
- Cumberland
- Cumming
- Curlew
- Cushing
- Cylinder
