River IL FL

Otter Slough

Illinois • 40.8587, -91.0605

Reviewed mapped path Updated Dec 30, 2025

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USGS and NOAA data is for informational purposes. Source notes

Length

4 mi

6 km

Elevation

524′ → 523′

1 ft drop

Stream Order

Major River

Slope

0.01%

0.3 ft/mi

Drainage

209,962 mi²

543,800 km²

Avg Flow

-- cfs

3.0 mph velocity

Path to Mouth

954 mi

1,535 km to ocean

Classification

Tributary

Mid-reach

Elevation Profile

Water Quality

Data from EPA Water Quality Portal (USGS, EPA, state agencies).

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Data from USGS & NOAA for informational purposes only. Read source and safety notes

Rain Radar