69 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Port Huron | 1 | 28,193 | 28,974 | -0.53% | 3,480 | 8 | City |
| Port Huron | 2 | 28,193 | 28,935 | -0.53% | 3,480 | 8 | City |
| Fort Gratiot charter | 3 | 11,864 | 11,234 | 1.46% | 743 | 16 | Township |
| Fort Gratiot charter | 4 | 11,864 | 11,229 | 1.46% | 743 | 16 | Township |
| Port Huron charter | 5 | 10,654 | 10,796 | -0.14% | 830 | 13 | Township |
| Port Huron charter | 6 | 10,654 | 10,789 | -0.14% | 830 | 13 | Township |
| Marysville | 7 | 9,835 | 9,999 | -0.33% | 1,342 | 7 | City |
| Marysville | 8 | 9,835 | 9,999 | -0.33% | 1,342 | 7 | City |
| Kimball | 9 | 9,626 | 9,607 | 0.01% | 259 | 37 | Township |
| Kimball | 10 | 9,626 | 9,620 | 0.01% | 259 | 37 | Township |
| Clay | 11 | 8,250 | 8,452 | -0.33% | 233 | 35 | Township |
| Clay | 12 | 8,250 | 8,447 | -0.33% | 233 | 35 | Township |
| St. Clair | 13 | 7,138 | 7,086 | 0.11% | 186 | 38 | Township |
| St. Clair | 14 | 7,138 | 7,098 | 0.11% | 186 | 38 | Township |
| St. Clair | 15 | 5,913 | 5,469 | 1.53% | 2,011 | 3 | City |
| St. Clair | 16 | 5,913 | 5,468 | 1.53% | 2,011 | 3 | City |
| Pearl Beach | 17 | 5,742 | 5,395 | 3.52% | 1,195 | 5 | CDP |
| Clyde | 18 | 5,417 | 5,520 | -0.26% | 152 | 36 | Township |
| Clyde | 19 | 5,417 | 5,517 | -0.26% | 152 | 36 | Township |
| Ira | 20 | 5,112 | 4,973 | 0.55% | 300 | 17 | Township |
| Ira | 21 | 5,112 | 4,988 | 0.55% | 300 | 17 | Township |
| Casco | 22 | 4,387 | 3,995 | 1.39% | 119 | 37 | Township |
| Casco | 23 | 4,387 | 4,018 | 1.39% | 119 | 37 | Township |
| Columbus | 24 | 4,296 | 4,108 | 0.68% | 117 | 37 | Township |
| Columbus | 25 | 4,296 | 4,126 | 0.68% | 117 | 37 | Township |
| Mussey | 26 | 4,164 | 4,239 | -0.26% | 117 | 36 | Township |
| Mussey | 27 | 4,164 | 4,239 | -0.26% | 117 | 36 | Township |
| Algonac | 28 | 4,090 | 4,197 | -0.51% | 2,882 | 1 | City |
| Algonac | 29 | 4,090 | 4,192 | -0.51% | 2,882 | 1 | City |
| Burtchville | 30 | 4,037 | 4,076 | -0.05% | 260 | 16 | Township |
| Burtchville | 31 | 4,037 | 4,073 | -0.05% | 260 | 16 | Township |
| Marine City | 32 | 3,989 | 4,075 | -0.42% | 1,850 | 2 | City |
| Marine City | 33 | 3,989 | 4,072 | -0.42% | 1,850 | 2 | City |
| East China | 34 | 3,659 | 3,704 | 0% | 555 | 7 | Township |
| East China | 35 | 3,659 | 3,704 | 0% | 555 | 7 | Township |
| China | 36 | 3,493 | 3,503 | -0.23% | 102 | 34 | Township |
| China | 37 | 3,493 | 3,503 | -0.23% | 102 | 34 | Township |
| Cottrellville | 38 | 3,484 | 3,412 | 1.34% | 167 | 21 | Township |
| Cottrellville | 39 | 3,484 | 3,412 | 1.34% | 167 | 21 | Township |
| Riley | 40 | 3,181 | 3,200 | -0.22% | 83 | 38 | Township |
| Riley | 41 | 3,181 | 3,198 | -0.22% | 83 | 38 | Township |
| Wales | 42 | 3,166 | 3,179 | -0.28% | 85 | 37 | Township |
| Wales | 43 | 3,166 | 3,180 | -0.28% | 85 | 37 | Township |
| Berlin | 44 | 3,125 | 3,119 | -0.03% | 84 | 37 | Township |
| Berlin | 45 | 3,125 | 3,117 | -0.03% | 84 | 37 | Township |
| Casco | 46 | 2,940 | 2,798 | 1.07% | 76 | 39 | Township |
| Casco | 47 | 2,940 | 2,807 | 1.07% | 76 | 39 | Township |
| Emmett | 48 | 2,519 | 2,515 | -0.04% | 71 | 35 | Township |
| Emmett | 49 | 2,519 | 2,516 | -0.04% | 71 | 35 | Township |
| Kenockee | 50 | 2,371 | 2,407 | -0.34% | 67 | 36 | Township |
| Kenockee | 51 | 2,371 | 2,406 | -0.34% | 67 | 36 | Township |
| Capac | 52 | 1,935 | 1,989 | -0.57% | 1,041 | 2 | Village |
| Capac | 53 | 1,935 | 1,988 | -0.57% | 1,041 | 2 | Village |
| Yale | 54 | 1,872 | 1,900 | -0.32% | 1,363 | 1 | City |
| Yale | 55 | 1,872 | 1,899 | -0.32% | 1,363 | 1 | City |
| Brockway | 56 | 1,869 | 1,895 | -0.27% | 56 | 34 | Township |
| Brockway | 57 | 1,869 | 1,894 | -0.27% | 56 | 34 | Township |
| Greenwood | 58 | 1,472 | 1,490 | -0.41% | 41 | 36 | Township |
| Greenwood | 59 | 1,472 | 1,489 | -0.41% | 41 | 36 | Township |
| Lynn | 60 | 1,114 | 1,124 | 0% | 31 | 36 | Township |
| Lynn | 61 | 1,114 | 1,123 | 0% | 31 | 36 | Township |
| Memphis | 62 | 1,084 | 1,079 | 0.09% | 966 | 1 | City |
| Memphis | 63 | 1,084 | 1,079 | 0.09% | 966 | 1 | City |
| Lakeport | 64 | 998 | 784 | 7.2% | 965 | 1 | CDP |
| Ruby | 65 | 901 | 630 | 7.13% | 240 | 4 | CDP |
| Emmett | 66 | 235 | 239 | -0.42% | 157 | 1 | Village |
| Emmett | 67 | 235 | 239 | -0.42% | 157 | 1 | Village |
| Columbus | 68 | 161 | 169 | -1.23% | 1 | 140 | Township |
| Columbus | 69 | 161 | 169 | -1.23% | 1 | 140 | Township |
Port Huron is the largest city in St. Clair County, with a population of 28,193.
Columbus is the smallest city in St. Clair County, with a population of 161.
There are 69 cities in St. Clair County, Michigan.