26 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Rochester | 1 | 124,648 | 121,575 | 0.41% | 2,194 | 57 | City |
| Byron | 2 | 7,050 | 6,327 | 1.75% | 2,268 | 3 | City |
| Stewartville | 3 | 7,036 | 6,684 | 0.85% | 2,132 | 3 | City |
| Marion | 4 | 4,164 | 4,031 | -0.02% | 143 | 29 | Township |
| Cascade | 5 | 2,861 | 2,837 | 0.46% | 248 | 12 | Township |
| Oronoco | 6 | 2,535 | 2,448 | -0.04% | 81 | 31 | Township |
| Rochester | 7 | 2,332 | 2,079 | 2.15% | 130 | 18 | Township |
| Oronoco | 8 | 2,155 | 1,809 | 2.77% | 735 | 3 | City |
| Eyota | 9 | 2,038 | 1,999 | 0.34% | 1,207 | 2 | City |
| Haverhill | 10 | 1,494 | 1,498 | 0.4% | 47 | 32 | Township |
| New Haven | 11 | 1,306 | 1,260 | 0.77% | 39 | 34 | Township |
| Kalmar | 12 | 1,178 | 1,123 | 0.86% | 36 | 33 | Township |
| Salem | 13 | 1,082 | 1,090 | 0.37% | 30 | 36 | Township |
| High Forest | 14 | 941 | 968 | -0.42% | 24 | 40 | Township |
| Dover | 15 | 764 | 784 | -0.39% | 761 | 1 | City |
| Pleasant Grove | 16 | 737 | 751 | 0.27% | 21 | 36 | Township |
| Rock Dell | 17 | 687 | 684 | 0.15% | 19 | 36 | Township |
| Orion | 18 | 530 | 546 | -0.56% | 15 | 36 | Township |
| Viola | 19 | 526 | 549 | -0.57% | 15 | 36 | Township |
| Eyota | 20 | 503 | 487 | 0% | 15 | 34 | Township |
| Dover | 21 | 379 | 385 | -0.52% | 11 | 35 | Township |
| Elmira | 22 | 372 | 349 | 1.64% | 11 | 35 | Township |
| Quincy | 23 | 339 | 328 | 0% | 9 | 36 | Township |
| Byron | 24 | 200 | 210 | -1.48% | 6 | 36 | Township |
| Byron | 25 | 158 | 150 | 0.64% | 4 | 36 | Township |
| Hammond | 26 | 128 | 131 | 0% | 800 | 0 | City |
Rochester is the largest city in Olmsted County, with a population of 124,648.
Hammond is the smallest city in Olmsted County, with a population of 128.
There are 26 cities in Olmsted County, Minnesota.