How high is the Rock River at Byron, IL right now?

The Rock River at Byron, IL is currently flowing at 5,540 cubic feet per second with a gage height of 6.83 feet, based on the most recent USGS instantaneous reading.

Is the flow on the Rock River at Byron, IL normal for this time of year?

Current flow is classified as normal for June 11. Today's discharge is at the 26th percentile compared to the long-term historical record at this gauge.

Is the Rock River at Byron, IL at flood stage?

No — the gage height is 6.17 feet below the NWS flood-stage threshold of 13.0 feet.

What is the historical median flow for the Rock River at Byron, IL on June 11?

The long-term median discharge for this date is 8,320 cfs based on USGS daily statistics. The 10th–95th percentile range historically is 3,270 to 23,100 cfs.

Where is the Rock River at Byron, IL stream gauge located?

The Rock River at Byron, IL stream gauge is operated by the USGS in Ogle County, IL on the Rock River. USGS site number 05440700 (coordinates 42.1222, -89.2554).

Rock River at Byron, IL

USGS Site No: 05440700 • Rock River • Ogle County, IL

Rock River at Byron, IL on the Rock River is currently at 5,540 cfs (Normal — 26th percentile for this date) . Gage height: 6.83 ft.

Reading from 1 week ago

↑ Upstream on Rock River

Rock River at Rockton, IL

Downstream on Rock River ↓

Rock River at Dixon, IL

5,540

CFS Discharge

6.83

Gage Height (ft)

Normal

Flow Condition

Normal

Flood Status

Historical Percentile Comparison

Today's discharge compared to the long-term record for June 11 at this station. Percentile rank shows what fraction of historical years had lower flow on this date.

Percentile	Label	CFS Threshold	Today's Flow
10th	Very Low threshold	3,270
25th	Low threshold	5,480
50th (Median)	Normal (median)	8,320	Today: 5,540 cfs
75th	High threshold	12,400
95th	Very High threshold	23,100

30-Day Hydrograph

Recent discharge plotted against the historical 10th–95th percentile envelope for the same calendar days. Source: USGS daily values + long-term statistics.

10th–95th historical Day-of-year median Recent discharge

30-Day Flow History

Date	Discharge (CFS)	Gage Ht (ft)
May 28, 2026	5,380	—
May 27, 2026	5,400	6.76
May 26, 2026	6,220	7.13
May 25, 2026	6,340	7.18
May 24, 2026	6,580	7.28
May 23, 2026	6,740	7.35
May 22, 2026	6,950	7.44
May 21, 2026	7,150	7.52
May 20, 2026	7,390	7.62
May 19, 2026	7,620	7.71
May 18, 2026	7,810	7.79
May 17, 2026	8,100	7.91
May 16, 2026	8,510	8.07
May 15, 2026	8,720	8.15
Apr 20, 2026	30,400	14.66
Apr 19, 2026	31,800	15.00
Apr 18, 2026	28,000	14.00
Apr 17, 2026	24,300	13.00
Apr 16, 2026	20,000	11.72
Apr 15, 2026	13,900	9.82
Apr 14, 2026	11,100	8.83
Apr 13, 2026	11,000	8.82
Apr 12, 2026	11,300	8.93
Apr 11, 2026	11,500	8.99
Apr 10, 2026	11,200	8.86
Apr 9, 2026	11,100	8.85
Apr 8, 2026	12,400	9.30
Apr 7, 2026	14,400	9.97
Apr 6, 2026	16,400	10.64
Apr 5, 2026	16,900	10.80

Station Information

USGS Site No: 05440700
State: IL
County: Ogle County
Coordinates: 42.1222, -89.2554
Drainage Area: 7,990 mi²
Datum (ft): 666.0
HUC Code: 07090005

View on USGS NWIS →

Flood Stage Thresholds

Action Stage: 10.5 ft
Flood Stage: 13.0 ft
Moderate Flood: 14.0 ft
Major Flood: 16.0 ft

Currently 6.17 ft below flood stage.

Recent Extremes

Max discharge: 31,800 cfs

Apr 19, 2026
Min discharge: 2,720 cfs

Nov 15, 2025
Days at flood stage: 4

Computed from the local daily-values archive.

Nearby Gauges

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14.1 mi · 570 cfs

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18.2 mi · 73 cfs

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22.1 mi · 233 cfs

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Pecatonica River at Freeport, IL
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