Upper Tongue HUC8 10090101
A 6,566 km² sub-basin of the Missouri region in MT, WY. Drought coverage is from the US Drought Monitor (map of 2026-09-01); streamflow classes place each USGS gauge's latest reading against its own day-of-year record.
Health score
37
Stressed
Drought index
245
Severe
Area in D2+
45.24%
0% exceptional (D4)
Gauges below normal
100%
of 2 reporting
Median flow
30%
p7 of record
Water assets
4,192
198 springs · 1,128 wells
USGS gauges (2)
- Tongue River at State Line nr Decker MT0630630037 cfsp6 · much below normal
- Tongue River at Tongue R Dam nr Decker MT06307500102 cfsp7 · much below normal
Recent conditions
| Date | DSCI | D2+ % | Gauges low | Flow pct |
|---|---|---|---|---|
| 2026-09-07 | 245 | 45.24 | 2/2 | p7 |
Top water assets
- 69Babione Creekriver
- 69South Fork Little Tongue Riverriver
- 69Tongue Riverriver
- 69Little Goose Creekriver
- 69West Fork Big Goose Creekriver
- 69Columbus Creekriver
- 69Rapid Creekriver
- 69Sawmill Creekriver
- 69Prune Creekriver
- 69Trail Creekriver