49 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Waukegan | 1 | 88,294 | 89,122 | -0.16% | 3,646 | 24 | City |
| Buffalo Grove | 2 | 43,061 | 43,094 | -0.01% | 4,505 | 10 | Village |
| Mundelein | 3 | 33,192 | 31,539 | 0.84% | 3,034 | 11 | Village |
| Highland Park | 4 | 31,112 | 30,157 | 0.51% | 2,543 | 12 | City |
| North Chicago | 5 | 30,588 | 30,740 | -0.08% | 3,826 | 8 | City |
| Gurnee | 6 | 30,490 | 30,657 | -0.09% | 2,256 | 14 | Village |
| McHenry | 7 | 29,563 | 27,349 | 1.26% | 1,966 | 15 | City |
| Lake in the Hills | 8 | 28,595 | 28,927 | -0.19% | 2,794 | 10 | Village |
| Vernon Hills | 9 | 27,090 | 26,825 | 0.16% | 3,501 | 8 | Village |
| Round Lake Beach | 10 | 27,033 | 27,207 | -0.11% | 5,359 | 5 | Village |
| Zion | 11 | 24,509 | 24,731 | -0.15% | 2,468 | 10 | City |
| Grayslake | 12 | 21,284 | 21,218 | 0.05% | 1,950 | 11 | Village |
| Libertyville | 13 | 20,683 | 20,563 | 0.1% | 2,348 | 9 | Village |
| Lake Zurich | 14 | 20,046 | 19,787 | 0.21% | 2,896 | 7 | Village |
| Lake Forest | 15 | 19,788 | 19,349 | 0.37% | 1,150 | 17 | City |
| Deerfield | 16 | 19,142 | 19,130 | 0.01% | 3,456 | 6 | Village |
| Round Lake | 17 | 18,635 | 18,691 | -0.05% | 3,352 | 6 | Village |
| Antioch | 18 | 15,353 | 14,617 | 0.81% | 1,863 | 8 | Village |
| Lindenhurst | 19 | 14,659 | 14,374 | 0.33% | 3,238 | 5 | Village |
| Beach Park | 20 | 14,200 | 14,235 | -0.04% | 2,007 | 7 | Village |
| Wauconda | 21 | 14,048 | 14,068 | -0.02% | 2,770 | 5 | Village |
| Fox Lake | 22 | 10,906 | 10,963 | -0.08% | 1,392 | 8 | Village |
| Barrington | 23 | 10,569 | 10,706 | -0.22% | 2,290 | 5 | Village |
| Hawthorn Woods | 24 | 9,830 | 9,091 | 1.27% | 1,208 | 8 | Village |
| Lake Villa | 25 | 8,742 | 8,726 | 0.03% | 1,338 | 7 | Village |
| Long Grove | 26 | 8,401 | 8,377 | 0.05% | 678 | 12 | Village |
| Island Lake | 27 | 8,081 | 8,036 | 0.1% | 2,413 | 3 | Village |
| Lincolnshire | 28 | 8,041 | 7,941 | 0.21% | 1,763 | 5 | Village |
| Park City | 29 | 7,969 | 7,881 | 0.19% | 6,888 | 1 | City |
| Volo | 30 | 7,936 | 6,210 | 3.77% | 1,925 | 4 | Village |
| Round Lake Park | 31 | 7,922 | 7,664 | 0.55% | 3,838 | 2 | Village |
| Lakemoor | 32 | 6,589 | 6,174 | 1.06% | 1,242 | 5 | Village |
| Winthrop Harbor | 33 | 6,555 | 6,584 | -0.08% | 1,414 | 5 | Village |
| Johnsburg | 34 | 6,458 | 6,368 | 0.23% | 890 | 7 | Village |
| Lake Bluff | 35 | 5,595 | 5,609 | -0.04% | 1,373 | 4 | Village |
| Highwood | 36 | 5,493 | 5,087 | 1.25% | 7,629 | 1 | City |
| Kildeer | 37 | 4,791 | 4,080 | 2.55% | 1,111 | 4 | Village |
| Green Oaks | 38 | 4,105 | 4,110 | -0.02% | 1,029 | 4 | Village |
| Hainesville | 39 | 3,527 | 3,541 | -0.06% | 1,910 | 2 | Village |
| Wadsworth | 40 | 3,501 | 3,504 | 0% | 356 | 10 | Village |
| Round Lake Heights | 41 | 2,591 | 2,615 | -0.15% | 4,506 | 1 | Village |
| Oakwood Hills | 42 | 2,054 | 2,069 | -0.1% | 1,888 | 1 | Village |
| Third Lake | 43 | 1,113 | 1,116 | 0% | 1,893 | 1 | Village |
| McCullom Lake | 44 | 961 | 982 | -0.31% | 2,769 | 0 | Village |
| Holiday Hills | 45 | 601 | 616 | -0.33% | 643 | 1 | Village |
| Mettawa | 46 | 577 | 532 | 1.41% | 106 | 5 | Village |
| Indian Creek | 47 | 536 | 533 | 0.19% | 2,007 | 0 | Village |
| Trout Valley | 48 | 505 | 511 | -0.2% | 1,180 | 0 | Village |
| Old Mill Creek | 49 | 158 | 163 | -0.63% | 15 | 11 | Village |
Waukegan is the largest city in Lake County, with a population of 88,294.
Old Mill Creek is the smallest city in Lake County, with a population of 158.
There are 49 cities in Lake County, Illinois.