Rivermatics

USGS Streamgage 06101500

Marias River near Chester, MT

Marias River near Chester, MT is USGS streamgage 06101500 in Montana, monitoring river discharge in hydrologic subbasin 10030203. It sits on the Marias River, alongside 3 other gauges Rivermatics tracks on the same river. It drains a watershed of about 4,944 square miles. Discharge records at this site go back to 1921. Typical flow runs near 792.7 cfs in July and 524.2 cfs in April, with the higher of the two arriving in July. Rivermatics issues a daily machine-learned flow outlook for this gauge, reaching 14 days ahead.

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Gauge details

State
Montana
Drainage area
4,944 sq mi
Gauge elevation
2,823 ft
Subbasin (HUC-8)
10030203
Coordinates
48.30596, -111.08053
USGS site number
06101500
Records begin
1921-04-01 (105 years)
Rivermatics forecast
14-day flow outlook

14-day flow forecast

Based on observations through for Marias River near Chester, MT. Each day carries a median estimate and the band the model expects the flow to fall within — not a single number to plan against. Forecasts are re-issued daily; see the live screen for the current outlook.

Forecast daily mean discharge in cubic feet per second, by date
Date Low p10 Expected p50 High p90 Range
476 509 539
479 518 561
472 516 588
464 513 631
457 509 742
457 513 711
447 509 819
440 509 820
437 511 864
434 511 869
429 512 855
428 514 892
435 522 1,028
432 522 1,014

All values in cubic feet per second (cfs). Estimates only — do not use them for navigation or for any safety, rescue, or emergency decision.

Typical flow by month

Long-term daily discharge percentiles from the USGS record (up to 105 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 184.2 453.5 691.7
February 189.2 489.1 804.3
March 219.2 494.5 1,138.5
April 275.6 524.2 1,453.7
May 396.7 789.3 2,272.3
June 440.5 1,055.9 3,119.7
July 381.4 792.7 2,258.4
August 270.4 671.5 1,543.2
September 323.1 631.4 1,426.3
October 279.2 553 1,201.3
November 249.2 510.8 1,015.1
December 200.2 490.8 696.9

All values in cubic feet per second (cfs).

Common questions

When does Marias River near Chester, MT normally run highest?
June, on the long-term record. The median daily flow that month is about 1,055.9 cfs, against 453.5 cfs in January, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
What is a normal flow for Marias River near Chester, MT?
It depends on the month. In January, half of days historically fall near 453.5 cfs, with the middle 80% of days between 184.2 and 691.7 cfs. The month-by-month table on this page gives the full range.
How long has Marias River near Chester, MT been measured?
Discharge records at USGS site 06101500 begin in 1921, about 105 years, covering roughly 9,200 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
Is there a flow forecast for Marias River near Chester, MT?
Yes. Rivermatics trains a machine-learned model — a temporal-fusion transformer — on this basin's observed flows, weather, and snowpack, and issues a daily flow 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 the live gauge screen. Open live conditions to see the current outlook.
Where is Marias River near Chester, MT?
The gauge sits at 48.30596, -111.08053, in Montana, in hydrologic subbasin 10030203, at an elevation of about 2,823 feet, draining roughly 4,944 square miles.
Can I use Marias River near Chester, MT 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.

Upstream and downstream on the Marias River

Every gauge Rivermatics tracks on this river, ordered by drainage area — upstream first. See the Marias River in full.

Other gauges in this subbasin