Mississippi River at Chester, IL: flow right now vs. normal
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—flow right now
—of typical for this month
—gage height
The Mississippi River at Chester, IL gauge has averaged 210,182 cfs over 84 years of monthly records. Flow is usually highest in May (333,952 cfs) and lowest in January (133,177 cfs).
Typical flow by month
Highest in May (333,952 cfs), lowest in January (133,177 cfs).
Key figures
- Average flow
- 210,182 cfs
- Highest peak on record
- 1,060,000 cfs
- Year of that peak
- 1927
- Drainage area
- 708,600 sq mi
- Years of records
- 84
- Gauge elevation
- 341 ft
- River
- Mississippi River
- County
- Randolph
- State
- Illinois
Monthly numbers
| Month | Average | Median | Lowest | Highest |
|---|---|---|---|---|
| Jan | 133,177 cfs | 113,500 cfs | 45,400 cfs | 407,000 cfs |
| Feb | 151,379 cfs | 132,500 cfs | 53,000 cfs | 332,500 cfs |
| Mar | 252,504 cfs | 229,000 cfs | 80,400 cfs | 586,000 cfs |
| Apr | 330,589 cfs | 310,500 cfs | 120,000 cfs | 738,000 cfs |
| May | 333,952 cfs | 347,500 cfs | 114,000 cfs | 735,000 cfs |
| Jun | 305,280 cfs | 269,000 cfs | 76,550 cfs | 849,000 cfs |
| Jul | 254,687 cfs | 223,000 cfs | 69,100 cfs | 823,000 cfs |
| Aug | 164,442 cfs | 143,500 cfs | 68,800 cfs | 785,000 cfs |
| Sep | 147,354 cfs | 123,750 cfs | 64,300 cfs | 502,500 cfs |
| Oct | 153,387 cfs | 126,000 cfs | 59,500 cfs | 578,000 cfs |
| Nov | 154,111 cfs | 134,750 cfs | 59,500 cfs | 427,000 cfs |
| Dec | 139,220 cfs | 119,000 cfs | 47,400 cfs | 466,000 cfs |
Monthly averages of daily flow over the gauge's record. Lowest and highest are the extreme monthly averages for that month.
How Mississippi River at Chester, IL compares in Illinois
- Mississippi River at Chester, IL ranks #3 of 189 gauges in Illinois in this dataset by average flow.
- That places it in the top 2% in Illinois by average flow.
- The median average flow of gauges in Illinois is 99.5 cfs.
- Among all 2,293 gauges in the dataset, Mississippi River at Chester, IL ranks #4 by average flow.
Data: U.S. Geological Survey (USGS) (public domain, U.S. federal data).· Updated 2026-11-02 · Text generated from the data and checked against it.
Live values are provisional USGS data. Measurements only, not a safety assessment — for flood warnings see the National Weather Service. Official page: USGS 07020500.