Northern Mariana Islands Soil Surveys
Northern Mariana Islands has 2 USDA soil survey areas covering a wide range of landscapes and soil conditions. The most common soil order is Mollisols — grassland soils with a thick, dark, fertile topsoil rich in organic matter, making up roughly 22% of surveyed soils. Entisols — young soils with little profile development, often on floodplains or steep slopes account for another 21%.
In terms of drainage, 89% of Northern Mariana Islands soils are classified as well drained. Drainage class affects everything from septic system design to basement feasibility to garden planning. Use the survey area pages below to see drainage details for specific counties, or look up any address for an exact soil profile.
Soil Types
Mollisols
22% of surveyed soils
Fertile grassland soils with thick, dark topsoil. Among the best for agriculture, building, and gardening.
Entisols
21% of surveyed soils
Young soils with little development — found on floodplains, dunes, and steep slopes. Properties vary widely by setting.
Andisols
20% of surveyed soils
Volcanic ash soils — light, porous, and fertile. Excellent drainage, but low density can complicate foundations.
Alfisols
20% of surveyed soils
Moderately weathered forest soils with clay-enriched subsoil. Productive for agriculture, generally good for building and septic.
Inceptisols
7% of surveyed soils
Young but developing soils found in mountains and river terraces. Variable properties — check drainage and bedrock depth.
Oxisols
6% of surveyed soils
Deeply weathered tropical soils. Nutrient-poor despite appearing lush. Rare in the continental US.
Histosols
1% of surveyed soils
Organic peat and muck soils formed in wetlands. Very poor for building (compressible) and septic. Often in regulated wetlands.
Survey Areas
Islands of Agrigan, Alamagan, Anatahan, Pagan, and Sarigan, Commonwealth of the Northern Mariana IslandsIslands of Aguijan, Rota, Saipan and Tinian, Commonwealth of the Northern Mariana Islands