State soils
Alaska Soil Surveys
The short version
The most common soil here is E45-Arctic dwarf scrub-gravelly frozen circles, on about 2% of the land. E31-Boreal forest-silty slopes and E31-Boreal forest-gravelly colluvial slopes come next.
About 37% of the land drains well, and 44% stays wet for long stretches; groundwater comes within two feet of the surface under 64% of it.
USDA rates 91% of the land very limited for a standard septic drain field, and 87% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 9% of the land floods occasionally or more, and bedrock lies within 40 inches under 25% 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.
Alaska has 137 USDA soil survey areas covering a wide range of landscapes and soil conditions. The most common soil order is Inceptisols — young soils with minimal horizon development but more than Entisols, making up roughly 29% of surveyed soils. Spodosols — acidic forest soils with a distinctive leached layer, common under conifers account for another 21%.
In terms of drainage, 42% of Alaska soils are classified as well drained. About 52% of soils have some form of poor drainage, which is important to consider for septic systems and foundations. 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
Inceptisols
29% of surveyed soils
Young but developing soils found in mountains and river terraces. Variable properties — check drainage and bedrock depth.
Spodosols
21% of surveyed soils
Acidic forest soils with a leached layer. Common under conifers. Often have drainage issues from a compacted subsoil layer.
Gelisols
21% of surveyed soils
Permafrost soils. Extremely challenging for construction and septic. Found almost exclusively in Alaska.
Entisols
14% of surveyed soils
Young soils with little development — found on floodplains, dunes, and steep slopes. Properties vary widely by setting.
Histosols
8% of surveyed soils
Organic peat and muck soils formed in wetlands. Very poor for building (compressible) and septic. Often in regulated wetlands.
Andisols
2% of surveyed soils
Volcanic ash soils — light, porous, and fertile. Excellent drainage, but low density can complicate foundations.
Mollisols
2% of surveyed soils
Fertile grassland soils with thick, dark topsoil. Among the best for agriculture, building, and gardening.
Survey Areas
Alaska Peninsula - Aniakchak and Unimak Area, AlaskaAlaska Peninsula - Iliamna and Bristol Bay Lowlands Area, AlaskaAlaska Peninsula - Port Heiden and Port Moller Area, AlaskaAlaska Range - Brushkana Area, AlaskaAlaska Range - Clearwater Mountains and Susitna River Area, AlaskaAlaska Range - Granite Mountains Area, AlaskaAlaska Range - Nelchina Public Use Area, AlaskaAlaska Range - Parts Of Mentasta Mountains Area, AlaskaAlaska Range - Revelation Mountains and Stink River Area, AlaskaAlaska Range - Tordrillo Mountains and Happy River Area, AlaskaAleutian Islands - Agattu Island Area, AlaskaAleutian Islands - Amchitka Island Area, AlaskaAleutian Islands - Attu Island Area, AlaskaAleutian Islands - Kiska Island Area, AlaskaAleutian Islands - Little Simkin, Khvostof, Segula and Davidof Islands Area, AlaskaAleutian Islands - Sanak Islands Area, AlaskaAleutian Islands - Semisopotchnoi Island Area, AlaskaAleutian Islands - Unalaska and Andreanof Islands Area, AlaskaAleutian Mountains - Lake Clark Area, AlaskaAnchorage Area, AlaskaArctic National Wildlife Refuge - Beaufort Coastal Plain Area, AlaskaArctic National Wildlife Refuge - Brooks Range East Area, AlaskaArctic National Wildlife Refuge - Brooks Range West Area, AlaskaArctic National Wildlife Refuge - Davidson Mountains and Coleen River Area, AlaskaBarren Islands Area, AlaskaBeaufort Coastal Plain - Deadhorse Area, AlaskaBering Land Bridge National Preserve and Shishmarev Area, AlaskaBoundary Range - Chilkat River Area, AlaskaBristol Bay-Northern Alaska Peninsula, North and Bordering Areas, AlaskaBrooks Foothills - Killik, Chandler, and Anaktuvuk Rivers Area, AlaskaBrooks Foothills - Toolik River Area, AlaskaBrooks Range - Brooks Foothills - Lisburne Peninsula Area, AlaskaBrooks Range - Brooks Foothills Area, AlaskaBrooks Range - Gates Of The Arctic National Park and Preserve Area, AlaskaBrooks Range - Kobuk Valley National Park and Noatak Preserve Area, AlaskaBrooks Range and Davidson Mountains Area, AlaskaBrooks Range and Kobuk River - Nana Area, AlaskaBrooks Range and Ray Mountains Area, AlaskaCantwell Area, AlaskaCape Krusenstern National Monument and Bordering Area, AlaskaChatham Area, AlaskaChugach Mountains - Eagle River Area, AlaskaChugach National Forest - Kenai Peninsula East Area, AlaskaChugach National Forest - Kenai Peninsula West Area, AlaskaChugach National Forest - Prince William Sound Area, AlaskaChugach St. Elias and Boundary Ranges - Coastal Rainforest Area, AlaskaCopper River Area, AlaskaDe Long Mountains West and Noatak River Area, AlaskaDelta River Area, AlaskaDenali National Park and Preserve Area, AlaskaFort Greely and Donnelly Training Area, AlaskaFort Wainwright Area, AlaskaGerstle River Area, AlaskaGlacier Bay National Park and Preserve-Gustavus Area, AlaskaGreater Delta Area, AlaskaGreater Fairbanks Area, AlaskaGreater Nenana Area, AlaskaGulkana River Area, AlaskaHaines Area, AlaskaInterior Rivers - Lime Hills and Kuskokwim Mountains Area, AlaskaKachemak Bay State Wilderness Park Area, AlaskaKantishna Area, AlaskaKanuti National Wildlife Refuge Area, AlaskaKatmai National Park and Preserve Area, AlaskaKenai Mountains and Kachemak Bay State Park Area, AlaskaKenai National Wildlife Refuge Area, AlaskaKenai Peninsula - Kenai Fjords National Park and Bordering Area, AlaskaKetchikan Area, AlaskaKobuk Ridges and Valleys - Alatna Hills and Bordering Area, AlaskaKodiak Archipelago Area, AlaskaKuskokwim - Kaiyuh Mountains Area, AlaskaKuskokwim - Kilbuck Mountains Area, AlaskaKuskokwim Mountains and Bordering Area, AlaskaLower Kenai Peninsula - Northern Chugach Islands Area, AlaskaLower Kenai Peninsula Area, AlaskaMatanuska-Susitna Valley Area, AlaskaMiddleton Island Area, AlaskaNational Petroleum Reserve - Beaufort Coastal Plain Area, AlaskaNational Petroleum Reserve - Brooks Foothills North Area, AlaskaNational Petroleum Reserve - Brooks Foothills South Area, AlaskaNorth Copper River Area, AlaskaNorth Ogilvie Mountains - Step Mountains Area, AlaskaNorth Ogilvie and Yukon - Old Crow Basin Area, AlaskaNorth Star Area, AlaskaNowitna National Wildlife Refuge Area, AlaskaNulato Hills - Continental Divide and Blackburn Hills Area, AlaskaNulato Hills Area, AlaskaParts Of Wrangell - St. Elias National Park and Preserve Area, AlaskaPurcell Mountains, Pah River Flats and Koyukuk River Area, AlaskaRay Mountains - Kokrines Hills and Yukon River Area, AlaskaRay Mountains - Yukon Flats National Wildlife Refuge Northwest Area, AlaskaRay Mountains and Bordering Area, AlaskaRay Mountains and Yukon River Lowlands Area, AlaskaReindeer and Iditarod Rivers Area, AlaskaRobinson Mountains and Gulf of Alaska Coast Area, AlaskaSaint Paul Island Area, AlaskaSelawik National Wildlife Refuge Area, AlaskaSeward Area, AlaskaSeward Peninsula - Kotzebue Sound and Kivalik River Area, AlaskaSeward Peninsula and Nulato Hills Area, AlaskaSkagway-Klondike Gold Rush National Historical Park, AlaskaSouthern Baird Mountains and Kiana Hills Area, AlaskaSouthern Nulato Hills Area, AlaskaSouthern Wood-Tikchik Area, AlaskaSt. George Island Area, AlaskaSt. Lawrence Island Area, AlaskaSt. Mathew Island Area, AlaskaStewart River Training Site, AlaskaStikine Area, AlaskaTalkeetna and Chugach Mountains - Cook Inlet Area, AlaskaTanana - Kuskokwim Lowlands - Snohomish and Trimokish Hills Area, AlaskaTanana and Chatanika River Area, AlaskaTatlanika and Wood River Area, AlaskaTetlin National Wildlife Refuge - Tanana Kuskokwim Lowlands Area, AlaskaTogiak National Wildlife Refuge - Southwestern Part and Bordering Area, AlaskaTogiak National Wildlife Refuge-Ahklun Mountains Area, AlaskaTongass National Forest - Klukwah and Takshanuk Mountains Area, AlaskaTotchaket Area, AlaskaUpper Tanana Area, AlaskaWestern Ahklun Mountains Area, AlaskaWestern Interior Rivers Area, AlaskaWestern Kenai Peninsula Area, AlaskaWhite Hills - Kuparuk River Area, AlaskaWhite Mountains Area, AlaskaYakutat Area, AlaskaYentna Area, AlaskaYukon Delta National Wildlife Refuge - Kuskoskwim River Area, AlaskaYukon Delta National Wildlife Refuge - Nunivak Island Refuge Area, AlaskaYukon Delta National Wildlife Refuge - Western Part Area, AlaskaYukon Delta National Wildlife Refuge - Yukon River Area, AlaskaYukon Flats Area, AlaskaYukon River Lowlands - Koyukuk National Wildlife Refuge Area, AlaskaYukon River Lowlands and Innoko National Wildlife Refuge South Area, AlaskaYukon River Lowlands and Innoko National Wildlife Refuge, North Area, AlaskaYukon Tanana Uplands East and Bordering Area, AlaskaYukon Tanana Uplands West and Bordering Area, AlaskaYukon-Charley Rivers National Preserve, Alaska