Active USGS

St Marys River At Great Mills, MD

Updated August 2, 2026 at 11:15:00 AM · Provisional · Site 01661500

Current conditions

Historical trends

Hourly measurements

Detailed readings by hour, organized by day

Nearby stations

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Official USGS page: https://waterdata.usgs.gov/monitoring-location/USGS-01661500/ (may include cooperator information)