Mississippi River at Thebes, IL: flow right now vs. normal
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—flow right now
—of typical for this month
—gage height
The Mississippi River at Thebes, IL gauge has averaged 212,420 cfs over 92 years of monthly records. Flow is usually highest in May (338,165 cfs) and lowest in January (138,907 cfs).
Typical flow by month
Highest in May (338,165 cfs), lowest in January (138,907 cfs).
Key figures
- Average flow
- 212,420 cfs
- Highest peak on record
- 1,080,000 cfs
- Year of that peak
- 1844
- Drainage area
- 713,200 sq mi
- Years of records
- 92
- Gauge elevation
- 300 ft
- River
- Mississippi River
- County
- Alexander
- State
- Illinois
Monthly numbers
| Month | Average | Median | Lowest | Highest |
|---|---|---|---|---|
| Jan | 138,907 cfs | 115,000 cfs | 33,300 cfs | 461,000 cfs |
| Feb | 157,304 cfs | 137,000 cfs | 45,200 cfs | 360,500 cfs |
| Mar | 258,015 cfs | 240,000 cfs | 78,900 cfs | 608,000 cfs |
| Apr | 331,853 cfs | 313,750 cfs | 116,500 cfs | 751,000 cfs |
| May | 338,165 cfs | 336,500 cfs | 83,200 cfs | 760,000 cfs |
| Jun | 307,575 cfs | 273,750 cfs | 70,800 cfs | 846,500 cfs |
| Jul | 255,055 cfs | 227,500 cfs | 73,100 cfs | 828,000 cfs |
| Aug | 162,338 cfs | 143,000 cfs | 44,600 cfs | 787,000 cfs |
| Sep | 145,680 cfs | 126,000 cfs | 57,300 cfs | 499,500 cfs |
| Oct | 153,544 cfs | 122,000 cfs | 44,300 cfs | 573,000 cfs |
| Nov | 155,536 cfs | 137,000 cfs | 49,800 cfs | 473,000 cfs |
| Dec | 143,110 cfs | 122,000 cfs | 51,800 cfs | 502,000 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 Thebes, IL compares in Illinois
- Mississippi River at Thebes, IL ranks #2 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 Thebes, IL ranks #3 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 07022000.