Expansive Soil in Missouri: County Ratings
39 of the 114 rated counties in Missouri have a dominant shrink-swell rating of High or Very High. Each rating below is the NRCS shrink-swell class covering the largest share of the county's mapped soil acres, computed from USDA SSURGO data. Open a county for the full class breakdown and what it means for a slab foundation.
| County | Dominant class | High + Very High share | Survey coverage |
|---|---|---|---|
| Adair County | High | 59% | 99% |
| Andrew County | Moderate | 39% | 99% |
| Atchison County | Moderate | 17% | 99% |
| Audrain County | Very High | 91% | 99% |
| Barry County | Low | 13% | 98% |
| Barton County | Moderate | 12% | 99% |
| Bates County | Very High | 71% | 99% |
| Benton County | High | 41% | 93% |
| Bollinger County | Low | 5% | 99% |
| Boone County | High | 74% | 99% |
| Buchanan County | Moderate | 21% | 97% |
| Butler County | Low | 5% | 98% |
| Caldwell County | High | 83% | 100% |
| Callaway County | High | 67% | 99% |
| Camden County | High | 40% | 92% |
| Cape Girardeau County | Moderate | 3% | 98% |
| Carroll County | High | 70% | 99% |
| Carter County | Low | 0% | 99% |
| Cass County | High | 76% | 99% |
| Cedar County | Moderate | 5% | 95% |
| Chariton County | High | 70% | 98% |
| Christian County | Moderate | 19% | 100% |
| Clark County | Moderate | 53% | 99% |
| Clay County | High | 68% | 96% |
| Clinton County | High | 73% | 99% |
| Cole County | Moderate | 23% | 97% |
| Cooper County | High | 41% | 99% |
| Crawford County | Low | 11% | 100% |
| Dade County | Moderate | 2% | 97% |
| Dallas County | Moderate | 19% | 100% |
| Daviess County | High | 74% | 99% |
| DeKalb County | High | 69% | 99% |
| Dent County | Low | 0% | 100% |
| Douglas County | Moderate | 24% | 100% |
| Dunklin County | Moderate | 28% | 97% |
| Franklin County | Moderate | 13% | 98% |
| Gasconade County | Moderate | 38% | 98% |
| Gentry County | Moderate | 58% | 99% |
| Greene County | Moderate | 3% | 99% |
| Grundy County | Moderate | 61% | 99% |
| Harrison County | High | 60% | 100% |
| Henry County | Moderate | 39% | 95% |
| Hickory County | High | 55% | 97% |
| Holt County | Moderate | 20% | 98% |
| Howard County | Moderate | 30% | 99% |
| Howell County | Low | 14% | 100% |
| Iron County | Low | 3% | 99% |
| Jackson County | Moderate | 45% | 94% |
| Jasper County | High | 53% | 98% |
| Jefferson County | High | 38% | 98% |
| Johnson County | High | 57% | 100% |
| Knox County | Very High | 75% | 100% |
| Laclede County | Low | 11% | 100% |
| Lafayette County | Moderate | 25% | 98% |
| Lawrence County | Low | 3% | 100% |
| Lewis County | Very High | 64% | 98% |
| Lincoln County | High | 69% | 98% |
| Linn County | High | 79% | 100% |
| Livingston County | High | 82% | 99% |
| Macon County | High | 80% | 98% |
| Madison County | Low | 3% | 99% |
| Maries County | Low | 28% | 100% |
| Marion County | Very High | 52% | 98% |
| McDonald County | Low | 1% | 100% |
| Mercer County | Moderate | 47% | 99% |
| Miller County | Low | 29% | 99% |
| Mississippi County | Moderate | 35% | 94% |
| Moniteau County | Moderate | 22% | 99% |
| Monroe County | Very High | 85% | 97% |
| Montgomery County | Very High | 70% | 99% |
| Morgan County | Low | 30% | 97% |
| New Madrid County | Moderate | 40% | 95% |
| Newton County | Low | 5% | 100% |
| Nodaway County | Moderate | 42% | 99% |
| Oregon County | Moderate | 18% | 100% |
| Osage County | Moderate | 24% | 99% |
| Ozark County | High | 58% | 98% |
| Pemiscot County | Moderate | 52% | 93% |
| Perry County | Moderate | 9% | 98% |
| Pettis County | High | 73% | 100% |
| Phelps County | Low | 9% | 100% |
| Pike County | Low | 46% | 98% |
| Platte County | Moderate | 36% | 98% |
| Polk County | Moderate | 17% | 99% |
| Pulaski County | Low | 2% | 99% |
| Putnam County | High | 54% | 99% |
| Ralls County | Very High | 56% | 98% |
| Randolph County | High | 84% | 98% |
| Ray County | High | 76% | 99% |
| Reynolds County | Low | 3% | 99% |
| Ripley County | Moderate | 2% | 99% |
| Saline County | Moderate | 44% | 99% |
| Schuyler County | Moderate | 53% | 100% |
| Scotland County | Moderate | 56% | 99% |
| Scott County | Low | 16% | 97% |
| Shannon County | Low | 9% | 99% |
| Shelby County | Very High | 87% | 100% |
| St. Charles County | Moderate | 44% | 94% |
| St. Clair County | Low | 12% | 96% |
| St. Francois County | Low | 17% | 99% |
| St. Louis County | Moderate | 6% | 91% |
| Ste. Genevieve County | Moderate | 16% | 98% |
| Stoddard County | Moderate | 19% | 98% |
| Stone County | Low | 14% | 91% |
| Sullivan County | High | 55% | 100% |
| Taney County | Low | 22% | 97% |
| Texas County | Low | 11% | 100% |
| Vernon County | Moderate | 17% | 99% |
| Warren County | High | 55% | 98% |
| Washington County | Moderate | 20% | 99% |
| Wayne County | Low | 2% | 98% |
| Webster County | Moderate | 22% | 100% |
| Worth County | Moderate | 47% | 99% |
| Wright County | Low | 3% | 100% |
How these ratings are computed
Ratings come from USDA NRCS SSURGO soil survey data: for each soil component we take the maximum linear extensibility percent (lep_r) in the top 100 cm, apply the NRCS Handbook Part 618 class limits (Low under 3 percent, Moderate 3 to 6, High 6 to 9, Very High 9 and above), assign map units by plurality of component percent, and roll acres up to the county. Full details on the methodology section of the lookup page. A county rating is not a parcel-level geotechnical assessment.