Illinois River At Marseilles flow report
As of July 13, 2026, Illinois River At Marseilles is flowing at 9,900 cfs with a gage height of 12.75 ft, holding steady over the past 24 hours. Source: USGS gauge #05543500, refreshed throughout the day.
Historical Data
Illinois River At Marseilles at a glance
How Illinois River At Marseilles is running right now, where it sits on the map, and the key gauge stats.
Illinois River At Marseilles is flowing at 9,900 cfs, with the water sitting 12.75 ft at the gage. Flow has held roughly steady over the past 24 hours.
This is USGS gauge #05543500 in Illinois. Over the past 10 days the average has been 16,553 cfs, peaking at 33,400 cfs.
Over the next 5 days, Illinois River At Marseilles is expected to recede from today's 9470 cfs, toward roughly 7050 cfs by 2026-07-17 (likely range 3236-15358 cfs) -- drier than normal for the date.
For real-time updates and historical context, see the realtime view or the historical comparison. Browse other gauges in the Illinois flow report.
Streamflow Forecast
Powered by PULSE — Snoflo’s Predictive Unified Learning & Simulation Engine, which learns from how this river has answered every past storm, snowmelt, and dry spell to forecast where it’s headed with a precision generic models can’t match.
How does this compare to past years?
Year-over-year overlay, annual peak discharge, the full distribution of daily flows on record, and the gauge's rating curve.
Weather Forecast
Next 5 days, hour by hour
Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.
5-day forecast table
Every 3 hours, broken out across temperature, snow, rain, humidity, and wind.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
|---|---|---|---|---|---|---|---|
| Loading detailed forecast… | |||||||
15-day forecast
Daily temperatures, snow, and rain projected over the next two weeks.
Illinois River At Marseilles
The Dresden Island and Marseilles Dams also impact the flow. Seasonally, the river experiences high flows in the spring due to snowmelt and precipitation, and low flows in the summer and fall. Interestingly, the river is home to several rare and endangered species, including the Hine's Emerald dragonfly and the Alligator Snapping Turtle. Additionally, the river was once a popular site for paddlewheel steamboats and was even featured in Mark Twain's book "Life on the Mississippi."
Nearby streamflow levels
Cross-check Illinois River At Marseilles's discharge against nearby gauges to spot whether the change here is local or regional.
| Gauge | Streamflow |
|---|---|
| Illinois River At Marseilles | 9,900 cfs |
| Fox River At Dayton | 2,370 cfs |
| Vermilion River Near Leonore | 818 cfs |
| Mazon River Near Coal City | 108 cfs |
| Kankakee River Near Wilmington | 4,360 cfs |
| Blackberry Creek Near Yorkville | 107 cfs |
Nearby snowpack data
Snowpack at SNOTEL stations near Illinois River At Marseilles. Spring snowmelt is the dominant driver of streamflow in mountain basins -- a deep snowpack upstream means more runoff later in the season.
| SNOTEL station | Snowpack |
|---|---|
| Earlville | 0 in |
| La Salle 0.1 W | 0 in |
| Peru 0.7 Ene | 2 in |
| Morris 6.4 Ese | 0 in |
| Carbon Hill 3.1 N | 0 in |
| Coal City | 0 in |
Plan a trip
Reservoirs, boat launches, river runs, and fishing spots within driving distance of Illinois River At Marseilles.
Boat launches
See all →
River levels & flood safety
- Read the level before you go
- A river that's runnable at one flow can be deadly at another. Check current discharge and gage height — like the values shown above — against the flood-stage thresholds, and remember levels can spike fast after rain or a dam release.
- Respect cold water
- Snowmelt rivers run cold even in summer. Sudden immersion triggers cold-water shock and saps strength within minutes. Wear a PFD, dress for the water temperature (not the air), and never wade or paddle alone.
- Watch for swiftwater hazards
- Strainers (downed trees), undercut rocks, and low-head dams are the deadliest features on moving water. High, fast, muddy water hides them. If in doubt, scout from shore and portage.
- Mind flash floods & releases
- Narrow canyons can flood from a storm miles upstream, and dam-controlled reaches can rise without warning. Know the forecast, the release schedule, and your exit before you launch.
Track Illinois River At Marseilles in the Snoflo app
Save this gauge as a favorite, set push alerts when streamflow crosses a threshold (e.g. "alert me when Illinois River At Marseilles crosses 5,000 cfs"), and Snoflo's iOS app will push the moment USGS reports the crossing.
About Illinois River At Marseilles
Where does the streamflow data for Illinois River At Marseilles come from?
Discharge, gage height, and water temperature come directly from the USGS streamflow gauge 05543500. Snoflo refreshes the time series throughout the day. Forecasts come from the NOAA / yr.no feed Snoflo's iOS app uses.
How often is the report updated?
USGS gauges report continuously (typically every 15 minutes). Snoflo pulls fresh values throughout the day — look for the "as of" timestamp on the streamflow hero card.
What's the difference between discharge and gage height?
Discharge (cubic feet per second, or cfs) is the volume of water flowing past the gauge each second. Gage height is how high the water sits at the gauge (feet). They're related by a rating curve specific to each gauge — higher water means more flow, but the exact ratio depends on channel shape.
How is "percent of median" calculated?
Today's discharge is compared to the historical median discharge on this calendar day across the gauge's full record. 100% = right on median; 200% = a very high year; 30% = a drought-level low.
What are flood stages, and is this river safe right now?
Flood stages are NWS-defined gage-height thresholds — Action, Minor, Moderate, Major — marking when nearby roads or floodplains start to be affected. "Safe" depends on your activity and skill: a level that's a fun paddle for an expert can be lethal for a wader. Always check the current level against the thresholds above and the safety links, and when in doubt, stay off the water.
Can I get alerts when Illinois River At Marseilles rises?
Yes — flow alerts are managed in the Snoflo iOS app. Favorite this gauge, set a streamflow threshold (e.g. "alert me when discharge crosses 5,000 cfs"), and you'll get a push the moment USGS reports the crossing.
Access the free Illinois River At Marseilles report
Create your free account to track this river — and everything else you love on the water.
- Flow alerts — get pinged the moment this river hits your range
- Save favorites — every river, lake & snowpack in one place
- Full history & forecasts — plus the free iPhone app