Major Flood
15 ft
Current Water Level
Gage Height
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Streamflow
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Last Reading
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FLOOD STAGES
Know the flood categories.
Flood stages defined by the National Weather Service. Gage height data from USGS Water Resources.
Moderate Flood
12 ft
Minor Flood
10 ft
Action Stage
9.5 ft
What Floods at Each Level
15 ft
River Road flooding expands. The road closes between Grist Mill Drive and the Millstone Causway. Canal Road in Franklin Township floods.
12 ft
River Road flooding expands near the Griggstown Causeway and begins south of Dead Tree Run Road.
10 ft
River Road in Montgomery Township begins to flood near the Griggstown Causeway.
9.5 ft
Griggstown Causeway is closed.
Impact statements from the National Weather Service, describing what typically happens at each water level.
7-Day Water Level Chart
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Historic Crests
| Date | Stage | Flow |
|---|---|---|
| Aug 28, 2011 | 24.21 ft | — |
| Sep 2, 2021 | 23.36 ft | — |
| Sep 15, 1999 | 23.2 ft | — |
About This Gauge
USGS Site
NWS LID
GTNN4
River
Millstone River
County
Somerset, NJ
Coordinates
40.4400°N, 74.6175°W
Get Flood Alerts for Millstone River
StormCast monitors this gauge and sends a push notification to your phone when the water level crosses into a new flood category — even at 3 AM.
Frequently Asked Questions
What is the current water level of Millstone River at Griggstown?
The Millstone River at Griggstown gauge is maintained by USGS (site 01401750) and reports water levels every 15 minutes. Visit this page to see the latest reading updated live, or download StormCast to get push alerts when levels rise.
What is flood stage for Millstone River at Griggstown?
The NWS-defined flood stage for Millstone River at Griggstown is 10 feet. Action stage begins at 9.5 feet. Moderate flooding starts at 12 feet, and major flooding at 15 feet.
How do I get alerts when Millstone River rises?
Download StormCast free on Google Play, go to River Gauges, and add Millstone River at Griggstown to your watchlist. StormCast will send a push notification to your phone whenever the water level crosses into a new NWS flood category.
Where is the Millstone River at Griggstown gauge located?
The gauge is located in Somerset County, New Jersey at coordinates 40.4400°N, 74.6175°W. USGS site number: 01401750. Data is provided by the U.S. Geological Survey and the National Weather Service.
More Gauges on Millstone River
On This River
Downstream: Millstone River at Blackwells Mills
More Resources
Source & Notes
Data provided by: US Geological Survey, Observations courtesy of U.S. Geological Survey