Jackson Junction to Knoxville
(Click a column header to sort)
| City | Population |
| Jackson Junction | 60 |
| Jamaica | 237 |
| Janesville | 829 |
| Jefferson | 4,626 |
| Jesup | 2,212 |
| Jewell | 1,239 |
| Johnston | 13,596 |
| Joice | 231 |
| Jolley | 54 |
| Kalona | 2,293 |
| Kamrar | 229 |
| Kanawha | 739 |
| Kellerton | 372 |
| Kelley | 300 |
| Kellogg | 606 |
| Kensett | 280 |
| Keokuk | 11,427 |
| Keomah Village | 97 |
| Keosauqua | 1,066 |
| Keota | 1,025 |
| Keswick | 295 |
| Keystone | 687 |
| Kimballton | 342 |
| Kingsley | 1,245 |
| Kinross | 80 |
| Kirkman | 76 |
| Kirkville | 214 |
| Kiron | 273 |
| Klemme | 593 |
| Knierim | 70 |
| Knoxville | 7,731 |
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