River WA

Union River

Washington • 47.5000, -122.8029

Hydrography profile Updated Dec 30, 2025

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USGS and NOAA data is for informational purposes. Source notes

Length

12 mi

19 km

Elevation

915′ → 2′

913 ft drop

Stream Order

Medium River

Slope

1.48%

78.3 ft/mi

Drainage

22 mi²

57 km²

Avg Flow

-- cfs

0.9 mph velocity

Path to Mouth

11 mi

17 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

Access Sites on Union River

There are 1 boat ramps, launches, and public access points on Union River.