15 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Lincoln township | 1 | 4,769 | 4,531 | 1.36% | 113 | 42.39 | Township |
| Roselawn | 2 | 2,726 | 3,519 | -3.33% | 411 | 6.64 | CDP |
| Lake township | 3 | 2,453 | 2,357 | 1.11% | 62 | 39.78 | Township |
| Jefferson township | 4 | 2,019 | 2,003 | 0.45% | 45 | 45.13 | Township |
| Kentland | 5 | 1,599 | 1,633 | -0.44% | 1,184 | 1.35 | Town |
| Beaver township | 6 | 1,527 | 1,515 | 0.33% | 37 | 40.88 | Township |
| Iroquois township | 7 | 1,252 | 1,240 | 0.4% | 34 | 36.71 | Township |
| Grant township | 8 | 1,092 | 1,098 | 0.18% | 31 | 35.52 | Township |
| Morocco | 9 | 1,068 | 1,075 | -0.09% | 1,002 | 1.07 | Town |
| Goodland | 10 | 957 | 976 | -0.42% | 1,258 | 0.76 | Town |
| Brook | 11 | 932 | 937 | -0.11% | 1,377 | 0.68 | Town |
| Lake Village | 12 | 532 | 707 | -2.92% | 135 | 3.94 | CDP |
| Jackson township | 13 | 394 | 384 | 0.77% | 11 | 36.62 | Township |
| McClellan township | 14 | 224 | 215 | 0.9% | 5 | 42.30 | Township |
| Mount Ayr | 15 | 114 | 116 | 0% | 651 | 0.17 | Town |
Lincoln township is the largest city in Newton County, with a population of 4,769.
Mount Ayr is the smallest city in Newton County.
There are 15 cities in Newton County, Indiana.