102 counties mapped. On average, 25% of Illinois county soil area is high shrink-swell clay (USDA SSURGO).
Higher percentages mean more of a county's mapped soil is shrink-swell clay that expands and contracts with moisture. This is county-scale exposure, not a diagnosis of any single home — but it tells you whether soil movement belongs on your radar.
Foundation repair is one of the most over-sold jobs in home services — quotes for the same house can vary 3×. Before you sign anything, learn how to get honest bids and what a fair price looks like.
Before you call a foundation company →| County | Tier | High-risk % | Moderate % |
|---|---|---|---|
| Montgomery | Severe | 66% | 22% |
| Jasper | Severe | 59% | 15% |
| Clay | Severe | 58% | 15% |
| Richland | Severe | 58% | 17% |
| Macoupin | Severe | 58% | 27% |
| Christian | Severe | 56% | 39% |
| Effingham | Severe | 55% | 14% |
| Ford | Severe | 55% | 44% |
| Cumberland | Severe | 53% | 26% |
| Bond | Severe | 51% | 27% |
| Marion | Severe | 51% | 20% |
| Douglas | Severe | 50% | 49% |
| Fayette | Severe | 48% | 17% |
| Wayne | Severe | 47% | 12% |
| Livingston | Severe | 47% | 50% |
| Moultrie | Severe | 46% | 51% |
| Shelby | Severe | 45% | 37% |
| Clinton | Severe | 44% | 32% |
| Iroquois | Severe | 44% | 40% |
| Washington | Severe | 44% | 30% |
| Crawford | Severe | 43% | 23% |
| Hancock | Severe | 43% | 40% |
| McDonough | Severe | 42% | 46% |
| Franklin | Severe | 41% | 16% |
| Hamilton | Severe | 39% | 20% |
| Sangamon | Severe | 38% | 56% |
| Jefferson | Severe | 36% | 29% |
| Piatt | Severe | 36% | 62% |
| Adams | Severe | 35% | 42% |
| Clark | Severe | 35% | 37% |
| Woodford | Severe | 33% | 57% |
| Macon | Severe | 33% | 62% |
| Vermilion | Severe | 33% | 63% |
| Madison | Severe | 32% | 40% |
| Perry | Severe | 31% | 41% |
| DuPage | Severe | 31% | 62% |
| Schuyler | High | 30% | 37% |
| Edwards | High | 30% | 31% |
| Lawrence | High | 29% | 33% |
| Morgan | High | 29% | 60% |
| St. Clair | High | 28% | 48% |
| Jackson | High | 28% | 45% |
| Brown | High | 26% | 39% |
| Randolph | High | 25% | 51% |
| Cook | High | 25% | 37% |
| Logan | High | 24% | 71% |
| Champaign | High | 23% | 75% |
| La Salle | High | 23% | 69% |
| Alexander | High | 23% | 30% |
| Knox | High | 22% | 67% |
| Peoria | High | 22% | 53% |
| Monroe | High | 21% | 54% |
| Scott | High | 21% | 57% |
| Will | High | 21% | 66% |
| Williamson | High | 20% | 30% |
| Grundy | High | 19% | 65% |
| McLean | High | 19% | 78% |
| Stark | High | 19% | 75% |
| Fulton | High | 18% | 59% |
| Greene | High | 18% | 67% |
| Marshall | High | 18% | 64% |
| De Witt | High | 18% | 76% |
| Gallatin | High | 18% | 38% |
| Saline | High | 18% | 24% |
| Tazewell | High | 17% | 63% |
| Edgar | High | 15% | 80% |
| Menard | High | 15% | 73% |
| DeKalb | High | 15% | 84% |
| Jo Daviess | High | 15% | 63% |
| Lake | Moderate | 15% | 67% |
| Kendall | Moderate | 14% | 82% |
| Coles | Moderate | 13% | 83% |
| White | Moderate | 13% | 31% |
| Pulaski | Moderate | 13% | 51% |
| Jersey | Moderate | 13% | 71% |
| Wabash | Moderate | 13% | 49% |
| Cass | Moderate | 11% | 50% |
| Union | Moderate | 11% | 61% |
| Henry | Moderate | 11% | 71% |
| Kankakee | Moderate | 10% | 59% |
| Massac | Moderate | 10% | 49% |
| Mercer | Moderate | 9% | 62% |
| Stephenson | Moderate | 9% | 86% |
| Warren | Moderate | 9% | 81% |
| Pike | Moderate | 7% | 61% |
| Winnebago | Moderate | 7% | 74% |
| Kane | Moderate | 6% | 87% |
| Henderson | Moderate | 6% | 49% |
| Carroll | Moderate | 6% | 72% |
| Ogle | Low | 5% | 86% |
| Putnam | Low | 4% | 68% |
| Rock Island | Low | 3% | 62% |
| Lee | Low | 3% | 78% |
| Calhoun | Low | 3% | 31% |
| Johnson | Low | 2% | 53% |
| Pope | Low | 2% | 55% |
| McHenry | Low | 2% | 77% |
| Bureau | Low | 2% | 79% |
| Whiteside | Low | 2% | 45% |
| Boone | Low | 1% | 89% |
| Hardin | Low | 1% | 62% |
| Mason | Low | 1% | 38% |
Risk metrics are computed from USDA SSURGO soil survey data (linear extensibility of soil components, area-weighted by county). Soil varies lot to lot — this is county-scale context, not a substitute for a site-specific geotechnical or structural assessment.