| Code | Definition | Number of Accessions |
| 10.1.5 | Central Basin and Range | 1 |
| 10.1.6 | Colorado Plateaus | 15 |
| 10.2.1 | Mojave Basin and Range | 1 |
| 11.1.1 | Central California Foothills and Coastal Mountains | 2 |
| 12.1.1 | Madrean Archipelago | 1 |
| 13.1.1 | Arizona/New Mexico Mountains | 9 |
| 5.2.1 | Northern Lakes and Forests | 13 |
| 5.2.2 | Northern Minnesota Wetlands | 1 |
| 5.3.1 | Northern Appalachians and Atlantic Maritime Highlands | 7 |
| 5.3.3 | North Cental Appalachians | 6 |
| 6.2.11 | Klamath Mountains | 10 |
| 6.2.7 | Cascades | 4 |
| 7.1.8 | Coastal Range | 4 |
| 7.1.9 | Willamette Valley | 13 |
| 8.1.1 | Eastern Great Lakes and Hudson Lowlands | 8 |
| 8.1.10 | Erie Drift Plain | 6 |
| 8.1.2 | Lake Erie Lowland | 5 |
| 8.1.3 | Northern Appalachian Plateau and Uplands | 9 |
| 8.1.4 | North Central Hardwood Forests | 11 |
| 8.1.5 | Driftless Area | 14 |
| 8.1.6 | Southern Michigan/Northern Indiana Drift Plains | 1 |
| 8.1.7 | Northeastern Coastal Zone | 7 |
| 8.1.8 | Maine/New Brunswick Plains and Hills | 4 |
| 8.2.1 | Southeastern Wisconsin Till Plains | 15 |
| 8.2.2 | Huron/Erie Lake Plains | 1 |
| 8.2.3 | Central Corn Belt Plains | 13 |
| 8.2.4 | Eastern Corn Belt Plains | 47 |
| 8.3.1 | Northern Piedmont | 13 |
| 8.3.2 | Interior River Valleys and Hills | 24 |
| 8.3.3 | Interior Plateau | 18 |
| 8.3.4 | Piedmont | 2 |
| 8.3.5 | Southeastern Plains | 26 |
| 8.3.6 | Mississippi Valley Loess Plains | 1 |
| 8.3.7 | South Central Plains | 2 |
| 8.4.1 | Ridge and Valley | 2 |
| 8.4.2 | Central Appalachians | 2 |
| 8.4.3 | Western Allegheny Plateau | 4 |
| 8.4.4 | Blue Ridge | 4 |
| 8.4.5 | Ozark Highlands | 15 |
| 8.4.9 | Southwestern Appalachians | 2 |
| 8.5.1 | Middle Atlantic Coastal Plain | 15 |
| 8.5.2 | Mississippi Alluvial Plain | 7 |
| 8.5.3 | Southern Coastal Plain | 2 |
| 9.2.1 | Aspen Parkland/Northern Glaciated Plains | 5 |
| 9.2.2 | Lake Manitoba and Lake Agassiz Plain | 12 |
| 9.2.3 | Western Corn Belt Plains | 13 |
| 9.2.4 | Central Irregular Plains | 9 |
| 9.3.1 | Northwestern Glaciated Plains | 1 |
| 9.3.3 | Northwestern Great Plains | 6 |
| 9.4.2 | Central Great Plains | 1 |
| 9.4.4 | Flint Hills | 1 |
| 9.4.5 | Cross Timbers | 1 |