Rivermatics

3 USGS Streamgages · Mississippi River system

Jefferson River flows and levels

Jefferson River is gauged at 3 USGS streamgages in Montana, each tracked by Rivermatics. It feeds the Missouri River. It drains into the Mississippi River system. Drainage area at the gauges ranges from 7,616 square miles at Jefferson River near Twin Bridges, MT up to 9,558 at Jefferson River near Three Forks, MT. The gauged reach falls about 483 feet, from 4,564 feet down to 4,081. Rivermatics issues a daily machine-learned 14-day flow outlook at 2 of them.

Gauges on this river, upstream to downstream

Ordered by drainage area, which is how far down the river each gauge sits. April and July figures are long-term median daily flows for that month from the USGS record — historical normals, not a forecast and not today's reading.

USGS streamgages on this river, ordered upstream to downstream
Gauge State Drainage sq mi Elevation ft April p50 cfs July p50 cfs Forecast
Jefferson River near Twin Bridges, MT MT 7,616 4,564 1,849.3 1,470.3 14-day + temp
Jefferson River at Parsons Bdg near Silver Star, MT MT 7,759 4,427 1,658.3 909 —
Jefferson River near Three Forks, MT MT 9,558 4,081 2,077 1,267.1 14-day + temp

Typical flow by month at Jefferson River near Three Forks, MT

The furthest-downstream gauge on this river, so the fullest flow it carries here. Long-term daily discharge percentiles from the USGS record (up to 48 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.

Historical monthly discharge percentiles in cubic feet per second
Month Low p10 Typical p50 High p90 Range
January 712 1,085.2 1,633.5
February 792.7 1,126.2 1,732.8
March 962.8 1,342.9 2,076.8
April 1,177.3 2,077 3,583.7
May 1,255.6 3,306.8 7,031
June 1,469.6 4,080.7 9,869.7
July 353 1,267.1 4,543.9
August 157.9 441.1 1,763.5
September 308.7 703.3 1,928
October 819.6 1,290 2,240
November 1,018.3 1,389 2,206.3
December 783.3 1,142.6 1,827.7

All values in cubic feet per second (cfs).

Common questions

When does the Jefferson River run highest?
June, on the long-term record at Jefferson River near Three Forks, MT — the furthest-downstream gauge Rivermatics tracks on this river. Median daily flow there is about 4,080.7 cfs that month, against 441.1 cfs in August, the lowest. Upstream gauges peak on their own schedule; the table on this page gives April and July for each.
How many gauges are on the Jefferson River?
Rivermatics tracks 3 USGS streamgages on the Jefferson River, across Montana. Each has its own page with the site's full flow record and monthly normals. The river may carry other gauges that publish neither daily values nor discharge statistics; those are not tracked here.
Is there a flow forecast for the Jefferson River?
Yes, at 2 of the 3 gauges. Rivermatics trains a machine-learned model — a temporal-fusion transformer — on each basin's observed flows, weather and snowpack, and issues a daily outlook reaching 14 days ahead: a median estimate inside a confidence band, not a single number to bet on. Every forecast is scored against days the model never trained on, and that track record is published on each gauge's live screen.
What river system is the Jefferson River part of?
The Jefferson River drains into the Mississippi River system — it is a tributary somewhere in that chain, following the flowpath down to its terminal river. Rivermatics builds this from the USGS/geoconnex reference-mainstem network rather than from names.
Can I use Jefferson River data for flood or safety decisions?
No. Rivermatics provides estimates, not guarantees, and the readings and forecasts here may be delayed, inaccurate, or wrong. Do not use them for navigation or for any safety, rescue, or emergency decision. Check the National Weather Service and USGS directly, and use your own judgment.

Other rivers in the Mississippi River system

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