Grand Lake St Marys
Source: U.S. Geological Survey (Water Data for the Nation)
S 3 mph · rain 0%
S 2 mph · rain 1%
Level history
Last 30 days of daily means.
Field notes
As of Oct 25, 2026, Grand Lake St Marys stood at 870.49 (NAVD88) ft.
Over the past 7 days the lake has been falling (−0.08 ft), and it is −0.70 ft over 30 days.
Compared with a year ago (869.09 ft, same time of day), the lake is 1.40 ft higher.
Readings come from the USGS gauge “Grand Lake St Marys near Celina OH”. Gauge elevations are not directly comparable between lakes because each uses its own datum.
Lake facts
| Gauge / station | Grand Lake St Marys near Celina OH |
|---|---|
| Elevation datum | ft (NAVD88) |
| Gauge location | 40.5344, -84.5739 |
Nearby lakes
Common questions
Is Grand Lake St Marys rising or falling?
Over the last 7 days it changed −0.08 ft and over 30 days −0.70 ft.
How full is Grand Lake St Marys?
USGS publishes the water surface elevation for this gauge but not a percent-full figure, so we don't show one rather than estimate it.
How often is this page updated?
The page is rebuilt automatically every day from USGS's published data. Values can be revised later by the source agency.
Where does the data come from?
The U.S. Geological Survey's Water Data API (api.waterdata.usgs.gov), which publishes readings from USGS and partner gauges. Forecasts come from the National Weather Service.
Latest instantaneous reading; 7-day, 30-day and year-ago changes compare readings at the same hour. USGS data are provisional and subject to revision. This page is not affiliated with or endorsed by the USGS. See data sources.