Expansive Soil in Mississippi: County Ratings
11 of the 82 rated counties in Mississippi 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 |
|---|---|---|---|
| Adams County | Low | 12% | 92% |
| Alcorn County | Low | 3% | 99% |
| Amite County | Low | 4% | 100% |
| Attala County | Low | 1% | 100% |
| Benton County | Low | 0% | 99% |
| Bolivar County | Very High | 67% | 93% |
| Calhoun County | Low | 12% | 99% |
| Carroll County | Low | 3% | 98% |
| Chickasaw County | Low | 33% | 97% |
| Choctaw County | Low | 11% | 100% |
| Claiborne County | Low | 4% | 91% |
| Clarke County | Low | 14% | 98% |
| Clay County | Low | 47% | 98% |
| Coahoma County | Very High | 50% | 90% |
| Copiah County | Low | 18% | 99% |
| Covington County | Low | 7% | 99% |
| DeSoto County | Low | 4% | 93% |
| Forrest County | Low | 10% | 98% |
| Franklin County | Low | 11% | 98% |
| George County | Low | 16% | 98% |
| Greene County | Low | 28% | 99% |
| Grenada County | Low | 7% | 91% |
| Hancock County | Low | 0% | 98% |
| Harrison County | Low | 0% | 96% |
| Hinds County | Low | 3% | 98% |
| Holmes County | Low | 13% | 98% |
| Humphreys County | Very High | 93% | 96% |
| Issaquena County | Very High | 73% | 90% |
| Itawamba County | Low | 2% | 98% |
| Jackson County | Low | 7% | 87% |
| Jasper County | Low | 18% | 99% |
| Jefferson County | Low | 16% | 98% |
| Jefferson Davis County | Low | 8% | 100% |
| Jones County | Low | 8% | 98% |
| Kemper County | Low | 33% | 99% |
| Lafayette County | Low | 20% | 93% |
| Lamar County | Low | 26% | 99% |
| Lauderdale County | Low | 18% | 96% |
| Lawrence County | Low | 15% | 99% |
| Leake County | Low | 1% | 99% |
| Lee County | Low | 32% | 98% |
| Leflore County | Very High | 67% | 94% |
| Lincoln County | Low | 2% | 99% |
| Lowndes County | Low | 42% | 96% |
| Madison County | Low | 1% | 97% |
| Marion County | Low | 3% | 98% |
| Marshall County | Low | 1% | 99% |
| Monroe County | Low | 33% | 98% |
| Montgomery County | Low | 1% | 99% |
| Neshoba County | Low | 0% | 99% |
| Newton County | Low | 10% | 99% |
| Noxubee County | High | 62% | 99% |
| Oktibbeha County | Low | 45% | 99% |
| Panola County | Low | 5% | 97% |
| Pearl River County | Low | 6% | 99% |
| Perry County | Low | 17% | 99% |
| Pike County | Low | 0% | 99% |
| Pontotoc County | Low | 39% | 99% |
| Prentiss County | Low | 14% | 99% |
| Quitman County | Very High | 68% | 98% |
| Rankin County | Low | 19% | 96% |
| Scott County | Low | 32% | 100% |
| Sharkey County | Very High | 83% | 97% |
| Simpson County | Low | 15% | 99% |
| Smith County | Low | 6% | 99% |
| Stone County | Low | 10% | 99% |
| Sunflower County | Very High | 77% | 99% |
| Tallahatchie County | Low | 34% | 96% |
| Tate County | Low | 2% | 97% |
| Tippah County | Low | 19% | 99% |
| Tishomingo County | Low | 0% | 95% |
| Tunica County | Very High | 77% | 90% |
| Union County | Low | 11% | 99% |
| Walthall County | Low | 0% | 99% |
| Warren County | Low | 20% | 93% |
| Washington County | Very High | 70% | 93% |
| Wayne County | Low | 18% | 99% |
| Webster County | Low | 11% | 99% |
| Wilkinson County | Low | 21% | 98% |
| Winston County | Low | 10% | 99% |
| Yalobusha County | Low | 6% | 92% |
| Yazoo County | Low | 23% | 98% |
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.