St. Lawrence County, New York
The most common soil here is Tunbridge, on about 6% of the land: a fine sandy loam, gritty and crumbly. Muskellunge and Potsdam come next.
About 49% of the land drains well, and 34% stays wet for long stretches; groundwater comes within two feet of the surface under 58% of it.
USDA rates 94% of the land very limited for a standard septic drain field, and 81% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 1% of the land floods occasionally or more, and bedrock lies within 40 inches under 29% of it.
Soils change over short distances, so look up an address below for the soil at that exact spot and the reasons behind each rating.
The soils you're most likely standing on
The biggest named soils in St. Lawrence County, New York, each drawn five feet deep from its official USDA description, in its recorded colors.
Dots mark gravel; white flecks mark lime. Shares are by acres across the survey area, and each mapped patch usually mixes several of these soils.
The biggest mapped areas
The dominant drainage class is Well drained and the dominant hydrologic group is C (slow infiltration, moderate runoff). The most common soil order is Spodosols — acidic forest soils with a distinctive leached layer, common under conifers. This report summarizes the major soil map units across the survey area to help you understand what to expect when buying, building, or gardening in St. Lawrence County, New York. Search your address to find the exact soil composition, drainage, and series details at your specific location.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Water | 92K | Not rated | Not rated | ||
| Potsdam-Tunbridge-Crary complex, 3 to 15 percent slopes, very bouldery | 68K | Well drained | C | Very limited | Very limited |
| Insula-Rock outcrop complex, rolling | 55K | Well drained | Very limited | Very limited | |
| Muskellunge silty clay loam, 0 to 3 percent slopes | 54K | Somewhat poorly drained | D | Very limited | Very limited |
| Tunbridge-Lyman complex, 15 to 35 percent slopes, very rocky, very bouldery | 49K | Well drained | B | Very limited | Very limited |
| Colton-Duxbury-Adams complex, 3 to 15 percent slopes | 49K | Excessively drained | A | Somewhat limited | Very limited |
| Insula-Rock outcrop complex, hilly | 48K | Well drained | Very limited | Very limited | |
| Dawson-Fluvaquents-Loxley complex, frequently flooded | 43K | Very poorly drained | A/D | Very limited | Very limited |
| Adjidaumo silty clay, 0 to 3 percent slopes | 41K | Poorly drained | D | Very limited | Very limited |
| Potsdam-Tunbridge complex, 15 to 35 percent slopes, very bouldery | 40K | Well drained | C | Very limited | Very limited |
| Hogansburg loam, 3 to 8 percent slopes | 40K | Moderately well drained | B/D | Very limited | Very limited |
| Malone loam, 0 to 8 percent slopes, very stony | 33K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Crary-Potsdam complex, 3 to 15 percent slopes, very bouldery | 33K | Well drained | C/D | Very limited | Very limited |
| Muskellunge silty clay loam, 3 to 8 percent slopes | 32K | Somewhat poorly drained | D | Very limited | Very limited |
| Potsdam very fine sandy loam, 3 to 15 percent slopes, very bouldary | 31K | Well drained | C | Very limited | Very limited |
| Naumburg loamy fine sand | 30K | Poorly drained | A/D | Very limited | Very limited |
| Hogansburg and Grenville soils, 0 to 8 percent slopes, very stony | 30K | Moderately well drained | B/D | Very limited | Very limited |
| Swanton fine sandy loam | 29K | Poorly drained | C/D | Very limited | Very limited |
| Carbondale muck | 28K | Very poorly drained | A/D | Very limited | Very limited |
| Borosaprists and Fluvaquents, frequently flooded | 27K | Very poorly drained | A/D | Very limited | Very limited |
Soil Orders in This Area
The USDA classifies every soil into one of 12 soil orders. Here are the dominant orders found in this survey area.
What This Means
Building & Foundations
About 81% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, poor drainage in some areas. A geotechnical assessment is recommended before building.
Septic Systems
About 94% of soils are rated "very limited" for septic absorption fields. Despite good drainage overall, limitations may stem from shallow bedrock, steep slopes, or seasonal conditions. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.
Gardening & Agriculture
Well-drained soils on sloped terrain — good for most plants but watch for erosion. Terracing, contour planting, and mulching help retain moisture and topsoil. Drip irrigation is more effective than sprinklers on slopes.