Illinois River Flow
As of 2026-08-02, the Illinois River is flowing at a combined 71,350 cfs across 12 USGS streamgauges — 143% of normal for this time of year, versus a seasonal average of 50,046 cfs.
Total streamflow across the Illinois River was last observed at 71,350 cfs, and is expected to yield approximately 141,522 acre-ft of water today; about 143% of normal. River levels are high. Average streamflow for this time of year is 50,046 cfs, with recent peaks last observed on 2015-12-28 when daily discharge volume was observed at 632,800 cfs.
Maximum discharge along the river is currently at the Illinois River At Marseilles reporting a streamflow rate of 22,900 cfs. However, the streamgauge with the highest stage along the river is the Illinois River At Henry with a gauge stage of 15.52 ft. This river is monitored from 12 different streamgauging stations along the Illinois River, the highest being situated at an altitude of 1,202 ft, the Illinois River Near Kerby.
River streamflow levels
Daily aggregate streamflow across every monitored gauge along the Illinois River. Use the range buttons to zoom in on a specific period.
Total streamflow
Sum of all monitored streamgauges · daily
Every streamgauge along the Illinois River
All 12 USGS gauges Snoflo tracks for this river, with current flow, stage, recent change, percent of normal, and the gauge's all-time min / max. Click any header to sort. Cells are heatmapped relative to the column min/max -- darker blue = higher.
| Streamgauge▾ | Streamflow (cfs)▾ | Gauge stage (ft)▾ | 24h Δ (%)▾ | % Normal▾ | Min (cfs)▾ | Max (cfs)▾ | Elevation (ft)▾ |
|---|---|---|---|---|---|---|---|
|
Illinois River Near Kerby
OR
USGS 14377100
|
26 | 0.56 | 0.0 | 53% | 9 | 24,500 | 1,202 |
|
Illinois River At Savoy
AR
USGS 07194800
|
47 | 2.12 | -6.4 | 117% | 2 | 23,300 | 1,019 |
|
Illinois River At Hwy. 16 Near Siloam Springs Ar
AR
USGS 07195400
|
257 | 6.24 | -6.2 | 78% | 105 | 68,100 | 922 |
|
Illinois River South Of Siloam Springs
AR
USGS 07195430
|
206 | 2.73 | 1.0 | 32% | 87 | 162,000 | 913 |
|
Illinois River Near Watts
OK
USGS 07195500
|
309 | 2.48 | -11.7 | 87% | 69 | 101,000 | 881 |
|
Illinois River At Chewey
OK
USGS 07196090
|
417 | 2.85 | -8.6 | 92% | 73 | 109,000 | 806 |
|
Illinois River Near Tahlequah
OK
USGS 07196500
|
498 | 5.36 | 0.0 | 83% | 82 | 104,000 | 666 |
|
Illinois River Near Gore
OK
USGS 07198000
|
297 | 7.31 | 1.4 | 225% | 5 | 19,300 | 489 |
|
Illinois River At Marseilles
IL
USGS 05543500
|
22,900 | 15.36 | 160.5 | 364% | 504 | 104,000 | 459 |
|
Illinois River At Kingston Mines
IL
USGS 05568500
|
17,800 | 6.99 | 52.1 | 189% | 37 | 363,000 | 441 |
|
Illinois River At Henry
IL
USGS 05558300
|
16,500 | 15.52 | 76.7 | 195% | 452 | 153,000 | 440 |
|
Illinois River At Valley City
IL
USGS 05586100
|
12,300 | 3.81 | -12.1 | 78% | 2,060 | 184,000 | 433 |
Maximum streamflow discharge by year
The single highest aggregate discharge recorded each year. Spotting the multi-year trend reveals droughts vs. wet cycles long before the headline daily flow does.
Annual peak discharge
From the river's full record · one point per water year
Streamflow elevation profile
Each bubble is one gauge along the river, plotted by current streamflow (x-axis) vs elevation (y-axis), sized by gauge stage. Reading top-to-bottom traces the river from headwaters down to its mouth -- you can see flow accumulate as elevation drops.
Elevation vs streamflow
One point per monitored gauge · bubble size = gauge stage
Illinois River
The Illinois River is a 273-mile-long tributary of the Mississippi River that flows through the state of Illinois. It was an important trade route for Native American tribes and European explorers, serving as a vital transportation artery for the region. The river's hydrology is heavily managed through a series of reservoirs and dams, including the Dresden, Marseilles, Peoria, and LaGrange Locks and Dams. These structures help to regulate water levels for navigation and flood control. The river is also used for recreational activities such as boating, fishing, and camping, and it supports a variety of agricultural uses in the surrounding areas. In recent years, efforts have been made to improve water quality and protect the ecosystem of the Illinois River.
Recreation along the Illinois River
Fishing access and paddle runs Snoflo tracks within the watershed.
Track the Illinois River in the Snoflo app
Set per-gauge push alerts (e.g. "alert me when flow at the Russian R Nr Healdsburg crosses 5,000 cfs"), and Snoflo's iOS app pushes the moment USGS reports the crossing.
About the Illinois River
How is the Illinois River flowing right now?
As of 2026-08-02, the Illinois River is flowing at a combined 71,350 cfs across its USGS streamgauges, about 143% of normal for this date. The live per-gauge breakdown and 24-hour trend are shown above.
Is the Illinois River running high or low right now?
Check the percent-of-normal figure on this page: above 100% means the river is running higher than its seasonal average for the date, below 100% means lower. The per-gauge table shows which reaches are highest and lowest.
Where does the data for the Illinois River come from?
Streamflow and gauge stage data are sourced from the U.S. Geological Survey (USGS) National Water Information System. The aggregate flow shown at the top of the page is computed by Snoflo as the sum of all monitored gauges along the river.
How is "percent of normal" calculated?
Today's aggregate streamflow is compared to the historical average aggregate streamflow on this calendar day across the river's full record. 100% means right on average; values above 100% indicate above-normal flow (wet year); values below indicate below-normal (dry year or drought).
Why are some gauges showing very different flows?
Gauges along a river measure flow at different points: headwater gauges read what's coming off the snowpack or mountain runoff; downstream gauges integrate everything upstream, including tributary inputs. Wide spreads usually mean a tributary is contributing significantly between gauges.
What's the elevation profile chart showing?
Each bubble is one gauge along the river, plotted by streamflow (x-axis) and elevation (y-axis), sized by gauge stage. Reading top-down traces the river from headwaters to mouth -- you can see flow build as elevation drops.
Can I get alerts when a specific gauge crosses a threshold?
Yes -- alerts are managed in the Snoflo iOS app on a per-gauge basis. Open any individual streamgauge from the table above and favorite it to set a discharge threshold.