14 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Wayne township | 1 | 7,807 | 8,031 | -0.38% | 210 | 37.14 | Township |
| Portland | 2 | 6,095 | 6,324 | -0.75% | 1,251 | 4.87 | City |
| Dunkirk | 3 | 2,056 | 2,161 | -1.01% | 1,750 | 1.18 | City |
| Bearcreek township | 4 | 1,572 | 1,624 | -0.57% | 43 | 36.23 | Township |
| Penn township | 5 | 1,102 | 1,129 | -0.27% | 37 | 30.19 | Township |
| Redkey | 6 | 1,056 | 1,098 | -0.75% | 1,212 | 0.87 | Town |
| Jackson township | 7 | 954 | 988 | -0.52% | 26 | 36.34 | Township |
| Greene township | 8 | 914 | 941 | -0.33% | 26 | 35.25 | Township |
| Pike township | 9 | 822 | 842 | -0.24% | 22 | 37.27 | Township |
| Jefferson township | 10 | 669 | 694 | -0.59% | 19 | 35.13 | Township |
| Pennville | 11 | 609 | 624 | -0.49% | 1,225 | 0.50 | Town |
| Noble township | 12 | 592 | 613 | -0.5% | 19 | 31.13 | Township |
| Bryant | 13 | 231 | 238 | -0.43% | 724 | 0.32 | Town |
| Salamonia | 14 | 146 | 150 | -0.68% | 199 | 0.73 | Town |
Wayne township is the largest city in Jay County, with a population of 7,807.
Salamonia is the smallest city in Jay County.
There are 14 cities in Jay County, Indiana.