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Saint Marys River in Ohio

River48.3 mi
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Around Saint Marys River

10 mi

Public land: USGS PAD-US

About this river

Saint Marys River is a 48.3 mile river. Streamflow is measured at the USGS gauge ST. Marys River at Main ST. at Fort Wayne, IN (site 04182769). The National Hydrography Dataset places it at stream order 7. Reach geometry comes from the USGS National Hydrography Dataset.

Typical flow by month

2010 to 2025

Saint Marys River typically runs highest in March, at a median 1,240 cfs, and lowest in September, at 90 cfs. The highest flow on record for any single day is 13,300 cfs, in 2015.

Show the numbers
Typical flow by month at ST. Marys River at Main ST. at Fort Wayne, IN, in cfs
MonthTypical (cfs)Usual range (cfs)
January678188 to 1,730
February445171 to 1,360
March1,240431 to 2,090
April790310 to 1,940
May548266 to 1,760
June296140 to 815
July16180 to 623
August10366 to 181
September9046 to 147
October9939 to 226
November12750 to 294
December24157 to 793

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 15 years of record. Statistics published by the US Geological Survey for ST. Marys River at Main ST. at Fort Wayne, IN (site 04182769). 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 Saint Marys River, all of them public access. Ramp data comes from the USGS national boat-ramp inventory.

  • Grand Lake St. Marys State Park - Marina RampPublic
  • Grand Lake St. Marys State Park - Fries Channel RampPublic
  • Grand Lake St. Marys State Park - Mercelina ParkPublic
  • Grand Lake St. Marys State Park - Boat Club RampPublic
  • Grand Lake St. Marys State Park - Campground RampPublic
  • Van Wert Reservoir No. 2Public
  • Guldlin ParkSt. Marys RiverPublic
  • Maumee Dam Public Access SiteMaumee RiverPublic

Made to print

Put Saint Marys River on your wall

This river section as an art print, drawn over the real terrain with its miles, plus the trails, roads and peaks around it. Pick the colors and the size, and see the finished print before you buy. From $39, shipping included.

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