Jefferson HUC8 10020005
A 3,367 km² sub-basin of the Missouri region in MT. 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
74
Moderate
Drought index
174
Moderate
Area in D2+
0%
0% exceptional (D4)
Gauges below normal
0%
of 4 reporting
Median flow
65%
p32 of record
Water assets
877
32 springs · 107 wells
USGS gauges (4)
- Willow Creek near Harrison MT060350005 cfsp26 · normal
- Jefferson River near Twin Bridges, MT06026500469 cfsp30 · normal
- Jefferson River near Three Forks MT06036650394 cfsp34 · normal
- Jefferson River at Parsons Bdg nr Silver Star, MT06027600252 cfsp43 · normal
Recent conditions
| Date | DSCI | D2+ % | Gauges low | Flow pct |
|---|---|---|---|---|
| 2026-09-07 | 174 | 0 | 0/4 | p32 |
Top water assets
- 70Delmoe Lake Damreservoir
- 70Norwegian Creek Damreservoir
- 69O'Neil Creekriver
- 69South Fork State Creekriver
- 69Little Whitetail Creekriver
- 69South Boulder Riverriver
- 69South Fork State Creekriver
- 69Little Whitetail Creekriver
- 69Little Whitetail Creekriver
- 69Little Whitetail Creekriver