USDA SSURGO COUNTY SOIL REFERENCE

Ada County, Idaho Soil Summary

This page summarizes USDA SSURGO mapped soil information for Ada County, Idaho.

Mapped Land Coverage
100%678,885.93 mapped acres of 678,885.91 Census land acres

Coverage measures mapped SSURGO intersection with Census land geometry. It does not mean that every parcel or point has complete soil information.

Soil at a Glance

Largest mapped soil unit
Area not surveyed, access denied
Symbol: ANS4.7% of mapped area
Largest estimated component
AREA NOT SURVEYED
31,996.49 acres (4.71% of mapped area)
Mapped units & components
15 soil units • 15 component series
Distinct SSURGO map units & series
Dominant drainage class
Well drained
Highest acreage drainage class
Dominant hydrologic group
Group D
Runoff potential classification
Weighted average slope
15.89%
Terrain slope analysis
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County summaries provide regional context across mapped soil units. Address lookup combines available public datasets for the Census-matched location.

Mapped SSURGO Soil Units

Largest mapped soil units in Ada County ranked by intersected vector acreage
SymbolMap Unit NameMapped Acres% of Mapped Area
ANSArea not surveyed, access denied31,911.484.7%
61Typic Haplargids and Lithic Haplargids; thermic hills and mountains7,125.891.05%
15Torriorthents, Torripsamments, and Haplargids; hyperthermic fan piedmonts5,543.680.82%
29Lithic Torriorthents and Ustic Haplargids, shallow; mesic hills and mountains4,654.120.69%
21Lithic Torriorthents, Typic Haplocalcids, and Rock outcrop; hyperthermic hills and mountains3,844.080.57%
8215Clanalpine-Segura-Cleavage association3,020.010.44%
8230Stopatoe-Scuffe-Notstew association2,190.10.32%
45Typic Torriorthents and Typic Haplargids; thermic fan piedmonts1,993.650.29%
24Torripsamments and Torriorthents; hyperthermic dunes and alluvium1,753.620.26%
23Torriorthents and Torripsamments; hyperthermic basins1,683.780.25%
100Pookaloo-Cavehill-Rock outcrop association1,672.470.25%
SHBShano silt loam, 0 to 5 percent slopes1,453.610.21%
3226Stewval-Bellehelen-Rock outcrop association1,429.040.21%
1594Boton complex1,372.950.2%
282Palinor very gravelly loam, 2 to 15 percent slopes1,290.460.19%

Estimated Soil Components

Component acreage estimated from SSURGO component percentages
ComponentDrainage ClassHydrologic GroupEstimated Acres% of Mapped Area
AREA NOT SURVEYEDUnspecifiedUnspecified31,996.494.71%
Rock outcropExcessively drained, Well drainedD19,461.012.87%
UnnamedSomewhat poorly drained, Poorly drainedC/D7,588.921.12%
WaterSubaqueousD6,020.460.89%
Lithic TorriorthentsWell drained, Excessively drained, Somewhat excessively drainedD5,949.480.88%
Typic UdorthentsSomewhat poorly drainedB/D, C/D, D5,315.020.78%
StewvalWell drainedD5,263.280.78%
PalinorWell drainedD4,675.060.69%
PlayasSomewhat poorly drained, Poorly drained, Very poorly drained, Well drainedD4,597.640.68%
CleavageWell drainedD4,016.190.59%
TorripsammentsExcessively drained, Somewhat excessively drainedA3,911.380.58%
Typic HaplargidsWell drainedC, A, D, B3,863.850.57%
UnselWell drainedC3,540.290.52%
TorriorthentsSomewhat excessively drained, Excessively drained, Well drainedB, A, D3,432.420.51%
ChiaraWell drainedD3,261.870.48%
Component acreage is estimated from SSURGO map-unit component percentages. Component values are not independently mapped polygon boundaries.

Drainage Class Distribution

Well drained69.2%
469,783.68 acres
Unknown / Unmapped10.42%
70,749.92 acres
Somewhat excessively drained6.51%
44,176.53 acres
Excessively drained3.82%
25,916.72 acres
Somewhat poorly drained3.45%
23,434.5 acres
Moderately well drained2.8%
18,998.8 acres
Poorly drained1.89%
12,832.98 acres
Very poorly drained1.38%
9,377.96 acres
Subaqueous0%
27.3 acres

Hydrologic Soil Group Distribution

Group D43.6%
295,977.14 acres
Group C20.44%
138,787.06 acres
Group B12.47%
84,665.13 acres
Group A12.01%
81,564.73 acres
Group Unknown / Unmapped8.87%
60,210.66 acres
Group C/D1.42%
9,666.24 acres
Group B/D0.47%
3,191.38 acres
Group A/D0.18%
1,236.02 acres

Hydrologic soil groups are USDA/NRCS classifications related to runoff potential under specified soil conditions. They are not a property-level flood-risk rating.

Slope Characteristics

Weighted Average Slope: 15.89%
Nearly Level (0-2%)18.88%
128,194.56 acres
Gently Sloping (2-8%)27%
183,288.29 acres
Moderately Sloping (8-15%)10.74%
72,926.53 acres
Steep (15-30%)13.5%
91,647.12 acres
Very Steep (>30%)21.43%
145,453.42 acres
Unspecified Slope7.92%
53,788.46 acres

Sources & Methodology

USDA NRCS SSURGO

Mapped soil units, components, drainage classes, hydrologic groups, and slope ratings derived from official Soil Data Access REST services.

U.S. Census Bureau TIGER/Line

County land geometry used for county-level coverage calculation.

Coverage Method

Mapped acreage is calculated from true spatial vector intersection of county land geometry and SSURGO mapped soil polygons using NAD83 / CONUS Albers Equal Area projection (EPSG:5070).