| Species | Sites Reporting | Year |
|---|---|---|
| Cabbage White | 28 | 1991 |
| Pearl Crescent | 27 | 1991 |
| Monarch | 27 | 1991 |
| Common/Orange Sulphur | 26 | 1991 |
| Black Swallowtail | 26 | 1991 |
| Spring/Summer Azure | 24 | 1991 |
| Eastern Tailed Blue | 23 | 1991 |
| Great Spangled Fritillary | 21 | 1991 |
| Common Wood Nymph | 19 | 1991 |
| Eastern Tiger Swallowtail | 19 | 1991 |
| Silver Spotted Skipper | 18 | 1991 |
| European Skipper | 17 | 1991 |
| Viceroy | 15 | 1991 |
| Little Wood Satyr | 15 | 1991 |
| Red-Spotted Purple | 14 | 1991 |
| Eyed Brown | 13 | 1991 |
| Least Skipper | 13 | 1991 |
| Red Admiral | 13 | 1991 |
| Peck's Skipper | 13 | 1991 |
| Mourning Cloak | 12 | 1991 |
| Question Mark | 11 | 1991 |
| Tawny Edge | 10 | 1991 |
| Buckeye | 10 | 1991 |
| Black Dash | 9 | 1991 |
| Eastern Comma | 9 | 1991 |
| Silvery Checkerspot | 9 | 1991 |
| American Painted Lady | 8 | 1991 |
| Northern Pearly-eye | 7 | 1991 |
| Long Dash | 7 | 1991 |
| Banded Hairstreak | 6 | 1991 |
| Giant Swallowtail | 6 | 1991 |
| Hackberry Butterfly | 5 | 1991 |
| Fiery Skipper | 5 | 1991 |
| Mulberrywing | 5 | 1991 |
| Coral Hairstreak | 5 | 1991 |
| Crossline Skipper | 4 | 1991 |
| Dun Skipper | 4 | 1991 |
| Common Sootywing | 4 | 1991 |
| Broadwinged Skipper | 4 | 1991 |
| Baltimore Checkerspot | 3 | 1991 |
| Delaware Skipper | 3 | 1991 |
| Acadian Hairstreak | 3 | 1991 |
| Dion Skipper | 3 | 1991 |
| Meadow Fritillary | 3 | 1991 |
| Sachem | 3 | 1991 |
| Pipevine Swallowtail | 2 | 1991 |
| Little Yellow | 2 | 1991 |
| Broken Dash | 2 | 1991 |
| Hobomok Skipper | 2 | 1991 |
| Little Glassywing | 2 | 1991 |
| Northern Cloudywing | 2 | 1991 |
| Horace's Duskywing | 2 | 1991 |
| Variegated Fritillary | 2 | 1991 |
| Wild Indigo Duskywing | 1 | 1991 |
| Checkered White | 1 | 1991 |
| Edwards Hairstreak | 1 | 1991 |
| American Copper | 1 | 1991 |
| Silver-Bordered Fritillary | 1 | 1991 |
| Aphrodite | 1 | 1991 |
| Cloudless Sulphur | 1 | 1991 |
| Spicebush Swallowtail | 1 | 1991 |
| Two Spot Skipper | 1 | 1991 |
| Appalachian Brown | 1 | 1991 |
| Hoary Edge | 1 | 1991 |
| Checkered Skipper | 1 | 1991 |
| Zabulon Skipper | 1 | 1991 |
| Striped Hairstreak | 1 | 1991 |
| Great Gray Copper | 1 | 1991 |
| Gorgone Checkerspot | 1 | 1991 |
| Gray Hairstreak | 1 | 1991 |
| Bronze Copper | 1 | 1991 |
| Snout Butterfly | 1 | 1991 |
| Dusted Skipper | 1 | 1991 |
Illinois Butterfly Monitoring Network
The Illinois Butterfly Monitoring Network engages citizen scientists in the process of collecting quantitative data on butterfly populations.