Rock River in Illinois
Around here
Around Rock River
Source: USGS GNIS · Public land: USGS PAD-US
About this river
Rock River is a 62.1 mile river. Streamflow is measured at the USGS gauge Rock River at Rockton, IL (site 05437500). The National Hydrography Dataset places it at stream order 8. Reach geometry comes from the USGS National Hydrography Dataset.
Typical flow by month
1940 to 2026
Rock River typically runs highest in April, at a median 6,880 cfs, and lowest in September, at 2,750 cfs. The highest flow on record for any single day is 29,700 cfs, in 1975.
Show the numbers
| Month | Typical (cfs) | Usual range (cfs) |
|---|---|---|
| January | 3,100 | 2,070 to 4,500 |
| February | 3,110 | 2,200 to 5,300 |
| March | 6,570 | 4,900 to 10,200 |
| April | 6,880 | 4,810 to 10,500 |
| May | 5,340 | 3,510 to 7,720 |
| June | 4,180 | 2,440 to 6,960 |
| July | 3,100 | 2,000 to 5,290 |
| August | 2,800 | 1,640 to 4,400 |
| September | 2,750 | 1,610 to 3,940 |
| October | 2,840 | 1,610 to 4,270 |
| November | 3,345 | 2,130 to 4,800 |
| December | 3,280 | 2,100 to 4,700 |
Typical is the median of each month’s daily median values, and the usual range runs from the median 25th to the median 75th percentile, across about 87 years of record. Statistics published by the US Geological Survey for Rock River at Rockton, IL (site 05437500). Conditions on any given day can fall well outside the usual range. Check the current reading before you go.
Boat access nearby
8 mapped launches sit in the mapped area of Rock River, all of them public access. Ramp data comes from the USGS national boat-ramp inventory.
Embed this gauge on your site
Paste this snippet anywhere, an outfitter page, a club site, a trip report, to show Rock River's live streamflow, water level and 7-day trend. It reads the USGS gauge directly, updates itself, and links back here.
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