HomeAlaskaYukon-Koyukuk Census Area
Yukon-Koyukuk Census Area, Alaska
A shallow water table limits basements on 62% of Yukon-Koyukuk Census Area's mapped land, a higher share than 75% of US counties and the 4th highest of 22 Alaska counties. Shrink-swell clay limits houses without basements on 0%.
The soil survey maps 22% of the county's land area; these shares describe the mapped part. None of the county is in drought on the November 3, 2026 Drought Monitor map. FEMA's flood data list 1 flood losses here since 2016. 36% of homes were built before 1980, against 50% nationally; the median home dates from 1984.
Data as of November 3, 2026 · sources
expansive clay: shrink-swell limits slab homes
high water table: limits basements
in drought, November 3, 2026
of homes built before 1980
Soil under Yukon-Koyukuk Census Area
| Expansive clay (limits slab homes) | 0.0% |
| High water table (limits basements) | 61.8% |
| Septic fields very limited | 93.8% |
| Clay swell (LEP, by area) | 1.2% |
| High-swell land (LEP 6%+) | 0.1% |
| Mapped soil | 20,848,206 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Seventeenmile | 4% | n/a |
| Yasuda | 2% | n/a |
| Tlozhavun | 2% | n/a |
| Tajittro | 2% | n/a |
| Gushdoiman | 1% | n/a |
| Kingslough | 1% | n/a |
How we count · survey areas AK630 (2025-08-29), AK643 (2025-08-29), AK655 (2025-09-02), AK685 (2025-09-02), AK728 (2025-09-02), AK729 (2025-09-02), AK749 (2025-09-02)
What the numbers mean here
On 62% of Yukon-Koyukuk Census Area's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
Rain over the 12 months to August 2026: 20.83 in, 5.00 in above the 1991-2020 average year of 15.83 in.
USDA rates 94% of the land very limited for septic absorption fields.
Drought
0% of the county is in drought (D1 or worse) on the November 3, 2026 map. Part of the county was in drought in 5 of the last 52 weeks; the most was 0.2% of its area, in 3 weeks, most recently on the August 25, 2026 map.
| Category, November 3, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 0% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
1 flood losses since 2016, $0 paid. The worst year was 2020, with 1.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 0 |
| 2018 | 0 |
| 2019 | 0 |
| 2020 | 1 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 15.83 in |
| 12 months to August 2026 | 20.83 in (+5.00) |
| 2025 | 17.40 in (+1.57) |
| Wettest year since 1925 | 1929: 19.75 in |
| Driest year since 1925 | 1969: 9.13 in |
| Days with 1 inch or more, normal at TANANA CALHOUN MEM AP (19 mi away) | 0.5 |
Homes
| Housing units | 3,724 |
| Median year built | 1984 |
| Built before 1980 | 36% |
| Built 2000 or later | 16% |
| Owner-occupied | 70% |
| Median value, owner-occupied | $98,500 |
| Single-family detached | 95% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Denali Borough, AK | 128 mi | n/a | n/a |
| Fairbanks North Star Borough, AK | 160 mi | 0% | 56% |
| Matanuska-Susitna Borough, AK | 226 mi | n/a | n/a |
| Northwest Arctic Borough, AK | 257 mi | 0% | 64% |
| Southeast Fairbanks Census Area, AK | 272 mi | 0% | 62% |
| North Slope Borough, AK | 285 mi | 0% | 67% |
| Anchorage Municipality, AK | 300 mi | 0% | 28% |
| Copper River Census Area, AK | 332 mi | 3% | 37% |
Sources: USDA SSURGO (September 2, 2025) · US Drought Monitor (November 3, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status