39 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Aurora | 1 | 180,935 | 180,260 | 0.06% | 3,999 | 45 | City |
| Naperville | 2 | 154,969 | 149,434 | 0.6% | 3,936 | 39 | City |
| Downers Grove | 3 | 152,484 | 149,641 | 0.79% | 3,071 | 50 | Township |
| York | 4 | 130,521 | 128,246 | 0.8% | 3,724 | 35 | Township |
| Aurora | 5 | 127,562 | 126,777 | 0.38% | 3,693 | 35 | Township |
| Lisle | 6 | 122,560 | 118,886 | 1.02% | 3,465 | 35 | Township |
| Bloomingdale | 7 | 113,315 | 111,705 | 0.73% | 3,316 | 34 | Township |
| Naperville | 8 | 109,503 | 104,627 | 1.12% | 3,138 | 35 | Township |
| Addison | 9 | 89,490 | 88,160 | 0.78% | 2,847 | 31 | Township |
| Wayne | 10 | 65,314 | 64,305 | 0.87% | 1,845 | 35 | Township |
| Wheaton | 11 | 53,662 | 53,899 | -0.07% | 4,741 | 11 | City |
| Downers Grove | 12 | 50,737 | 50,182 | 0.18% | 3,463 | 15 | Village |
| Winfield | 13 | 48,339 | 45,884 | 0.72% | 1,390 | 35 | Township |
| Elmhurst | 14 | 46,298 | 45,727 | 0.21% | 4,531 | 10 | City |
| Lombard | 15 | 44,527 | 44,416 | 0.04% | 4,383 | 10 | Village |
| Bartlett | 16 | 40,565 | 41,023 | -0.19% | 2,571 | 16 | Village |
| Carol Stream | 17 | 39,454 | 39,760 | -0.13% | 4,242 | 9 | Village |
| Addison | 18 | 35,776 | 35,631 | 0.07% | 3,640 | 10 | Village |
| Woodridge | 19 | 34,096 | 34,116 | -0.01% | 3,540 | 10 | Village |
| Glendale Heights | 20 | 32,749 | 33,100 | -0.18% | 6,071 | 5 | Village |
| Glen Ellyn | 21 | 28,837 | 28,941 | -0.06% | 4,184 | 7 | Village |
| West Chicago | 22 | 25,422 | 25,563 | -0.09% | 1,652 | 15 | City |
| Westmont | 23 | 24,256 | 24,412 | -0.11% | 4,837 | 5 | Village |
| Lisle | 24 | 23,490 | 23,664 | -0.12% | 3,406 | 7 | Village |
| Roselle | 25 | 22,845 | 22,923 | -0.06% | 4,131 | 6 | Village |
| Bloomingdale | 26 | 22,756 | 22,353 | 0.3% | 3,363 | 7 | Village |
| Darien | 27 | 22,023 | 21,998 | 0.02% | 3,571 | 6 | City |
| Villa Park | 28 | 21,927 | 22,206 | -0.21% | 4,644 | 5 | Village |
| Bensenville | 29 | 18,557 | 18,772 | -0.19% | 3,354 | 6 | Village |
| Hinsdale | 30 | 17,713 | 17,368 | 0.33% | 3,831 | 5 | Village |
| Warrenville | 31 | 16,055 | 13,631 | 2.58% | 2,939 | 5 | City |
| Wood Dale | 32 | 13,957 | 14,034 | -0.09% | 2,914 | 5 | City |
| Winfield | 33 | 10,393 | 9,810 | 0.94% | 3,358 | 3 | Village |
| Itasca | 34 | 9,488 | 9,541 | -0.09% | 1,889 | 5 | Village |
| Willowbrook | 35 | 9,158 | 9,221 | -0.11% | 3,557 | 3 | Village |
| Clarendon Hills | 36 | 8,710 | 8,689 | 0.05% | 4,812 | 2 | Village |
| Oak Brook | 37 | 8,208 | 8,148 | 0.12% | 1,029 | 8 | Village |
| Wayne | 38 | 2,287 | 2,280 | 0.04% | 399 | 6 | Village |
| Chicago | 39 | 0 | 0 | 0.00 | 3 | City |
Aurora is the largest city in DuPage County, with a population of 180,935.
Chicago is the smallest city in DuPage County, with a population of 0.
There are 39 cities in DuPage County, Illinois.