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Millstone River at Griggstown

Highest listed crest 24.21 ftFlood stage 10.0 ft29 crests since 1938

The Millstone River at Griggstown crested at major flood stage 14 times among the 29 crests the National Weather Service lists from 1938 to 2026. The highest, 24.21 ft on August 28, 2011, was major flooding, 14.21 feet above flood stage. 3 other gauges on the Millstone River crested above flood stage within a week of it, 1 at its own highest listed crest.

The gauge

Highest listed crest
24.21 ft
August 28, 2011
Flood stage
10.0 ft
Major flooding from 15.0 ft
Crests at major
14
4th of 125 gauges in New Jersey
Most recent flood crest
July 10, 2026
12.01 ft, moderate flooding
Location
Somerset County
Near Princeton (6.2 mi), Manville (7.2 mi), Somerville (9.0 mi)

Flood stages

The thresholds the National Weather Service uses for this gauge today, and how many listed crests reached each.

Flood categories, Millstone River at Griggstown
Action stage9.50—The level at which the NWS or its partners begin to take action
Flood stage (minor)10.07Mar 7, 2026Minimal or no property damage, but possibly some public threat
Moderate flood stage12.08Jul 10, 2026Some inundation of structures and roads near the stream
Major flood stage15.014Jan 10, 2024Extensive inundation of structures and roads

Every listed crest

29 crests from 1938 to 2026. Filled: at or above flood stage. Hover a crest for its date and stage.

Listed crests at the Millstone River at Griggstown, 1938 to 2026 10152025ft Flood stage 10.0 ftMajor 15.0 ft Sep 22, 1938: 19.00 ft, major floodingAug 28, 1971: 22.70 ft, major floodingOct 19, 1996: 18.00 ft, major floodingSep 16, 1999: 23.20 ft, major floodingApr 3, 2005: 14.65 ft, moderate floodingApr 16, 2007: 22.16 ft, major floodingMar 14, 2010: 18.65 ft, major floodingAug 28, 2011: 24.21 ft, major floodingMar 31, 2014: 13.78 ft, moderate floodingMay 1, 2014: 18.56 ft, major floodingMay 28, 2018: 16.29 ft, major floodingSep 29, 2018: 11.79 ft, minor floodingNov 17, 2018: 11.07 ft, minor floodingNov 25, 2018: 15.50 ft, major floodingJan 26, 2020: 10.13 ft, minor floodingDec 1, 2020: 13.02 ft, moderate floodingDec 26, 2020: 13.10 ft, moderate floodingMar 2, 2021: 11.56 ft, minor floodingJul 30, 2021: 11.45 ft, minor floodingAug 23, 2021: 17.24 ft, major floodingSep 2, 2021: 23.36 ft, major floodingApr 8, 2022: 13.91 ft, moderate floodingJul 16, 2023: 12.35 ft, moderate floodingDec 12, 2023: 11.91 ft, minor floodingDec 19, 2023: 16.49 ft, major floodingDec 29, 2023: 13.11 ft, moderate floodingJan 10, 2024: 15.96 ft, major floodingMar 7, 2026: 10.98 ft, minor floodingJul 10, 2026: 12.01 ft, moderate flooding Highest, 24.21 ft, Aug 28, 2011 19401960198020002020

Crests at or above flood stage, by decade

Crests at or above flood stage per decade, Millstone River at Griggstown 1930s: 1 1940s: 0 1950s: 0 1960s: 0 1970s: 1 1980s: 0 1990s: 2 2000s: 2 2010s: 8 2020s: 15 15 1930s1940s1950s1960s1970s1980s1990s2000s2010s2020s
  1. These are the crests the local National Weather Service office lists for the gauge: the highest on record and recent crests. Lesser floods between them may be missing, so counts by decade are a floor.
  2. Categories use today's flood stages. Levees, dams and channel changes since a crest can make old and new stages not directly comparable.

Highest crests

Highest listed crests, Millstone River at Griggstown
1Aug 28, 201124.21+14.21Major—
2Sep 2, 202123.36+13.36Major—
3Sep 16, 199923.20+13.20Major—
4Aug 28, 197122.70+12.70Major—
5Apr 16, 200722.16+12.16Major—
6Sep 22, 193819.00+9.00Major—
7Mar 14, 201018.65+8.65Major—
8May 1, 201418.56+8.56Major—
9Oct 19, 199618.00+8.00Major—
10Aug 23, 202117.24+7.24Major—
11Dec 19, 202316.49+6.49Major—
12May 28, 201816.29+6.29Major—
13Jan 10, 202415.96+5.96Major—
14Nov 25, 201815.50+5.50Major—
15Apr 3, 200514.65+4.65Moderate—
16Apr 8, 202213.91+3.91Moderate—
17Mar 31, 201413.78+3.78Moderate—
18Dec 29, 202313.11+3.11Moderate—
19Dec 26, 202013.10+3.10Moderate—
20Dec 1, 202013.02+3.02Moderate—
21Jul 16, 202312.35+2.35Moderate—
22Jul 10, 202612.01+2.01Moderate—
23Dec 12, 202311.91+1.91Minor—
24Sep 29, 201811.79+1.79Minor—
25Mar 2, 202111.56+1.56Minor—
26Jul 30, 202111.45+1.45Minor—
27Nov 17, 201811.07+1.07Minor—
28Mar 7, 202610.98+0.98Minor—
29Jan 26, 202010.13+0.13Minor—

The worst floods along the Millstone River

For this gauge's highest crests, the other gauges on the Millstone River that crested above flood stage within a week.

August 28, 2011: 24.21 ft here, major flooding

  • WestonNJ · Aug 28, 2011 · 22.90 ft · Major
  • MillstoneNJ · Aug 28, 2011 · 22.30 ft · Major
  • Blackwells MillsNJ · Aug 28, 2011 · 21.24 ft · Major · its highest

September 2, 2021: 23.36 ft here, major flooding

  • WestonNJ · Sep 2, 2021 · 23.75 ft · Major · its highest
  • MillstoneNJ · Sep 2, 2021 · 22.45 ft · Major · its highest
  • Blackwells MillsNJ · Sep 2, 2021 · 20.81 ft · Major

September 16, 1999: 23.20 ft here, major flooding

Gauges on the Millstone River

In USGS station-number order, which runs downstream within a river basin.

Flood gauges on the Millstone River
Griggstown this gaugeNJ10.024.21 ft, Aug 28, 201114
Blackwells MillsNJ9.021.24 ft, Aug 28, 201111
MillstoneNJ10.022.45 ft, Sep 2, 20216
WestonNJ11.523.75 ft, Sep 2, 20217

Other gauges in Somerset County

Flood gauges in Somerset County
Seeley Mills5.59.05 ft, Sep 2, 20210
Burnt Mills11.016.79 ft, Sep 2, 20214
Bound Brook11.020.66 ft, Sep 2, 20210
Burnt Mills9.512.76 ft, Sep 2, 20211
Blackwells Mills9.021.24 ft, Aug 28, 201111
Millstone10.022.45 ft, Sep 2, 20216
Weston11.523.75 ft, Sep 2, 20217
North Branch Village12.321.53 ft, Sep 16, 19990
South Branch8.020.26 ft, Sep 2, 202114
Far Hills6.07.60 ft, Jul 23, 19190
Raritan10.019.52 ft, Sep 2, 20216
Millington8.010.26 ft, Aug 29, 20112
Bound Brook28.042.13 ft, Sep 17, 199913
Manville14.027.66 ft, Sep 2, 202110
North Plainfield7.010.65 ft, Aug 2, 19730
Watchung14.024.50 ft, Aug 2, 19730
Martinsville6.011.47 ft, Sep 2, 20210

Somerset County: every hazard · River floods across the country · New Jersey

NOAA National Water Prediction Service, gauge GTNN4, retrieved October 30, 2026. Stages in feet on the gauge's own datum, not elevation. Crests are as the National Weather Service lists them; preliminary values may be revised.