Rivers in New Jersey

Millstone River at Blackwells Mills

Somerset County, New JerseyNWS BKWN4USGS 01402000Mount Holly office

Below flood stage
2.18ftStage

Observed Wed, Sep 23, 3:15 AM EDT

Flood stage
9.00 ft
Forecast crest
1.90 ftWed, Sep 23, 8:00 AM EDT
Record crest
21.24 ft2011

Open the live map with the river flood outlook

Flood stages and impacts

CategoryStage
Major flood15.00 ft
Moderate flood10.00 ft
Minor flood9.00 ft
Action7.00 ft
  1. 13.00 ftWashington Street and several businesses are flooded.
  2. 10.00 ftThe D&R Canal is flooded by the Millstone River.
  3. 9.00 ftFlood stage reached with flooding now along River Road in Blackwells Mills and S. River Street in Millstone. Base of Route 533 bridge floods. River Road between Yorktown and Amsterdam is subject to closure. Canal Road near Suydam Road floods.
  4. 7.00 ftSeveral more causeways are closed due to flooding.
  5. 6.00 ftThe Griggstown Causeway is closed due to flooding.

Flood outlook

Chance of flooding, September to November

CategoryChance
Minor flooding51%
Moderate flooding37%
Major flooding6%

The three-month chances are the River Forecast Centers’ long-range flood outlook, issued August 28, 2026.

Crest history

51 crests on NOAA’s list since 1938.

#DateStage
1August 28, 201121.24 ft
2September 17, 199921.01 ft
3September 2, 202120.81 ft
4April 16, 200719.24 ft
5August 28, 197118.68 ft
6July 15, 197516.84 ft
7March 14, 201016.15 ft
8May 1, 201415.87 ft
9October 20, 199615.53 ft
10September 21, 193815.29 ft
11January 20, 199615.09 ft
12July 21, 197514.63 ft
13September 21, 198914.42 ft
14August 23, 202114.30 ft
15December 19, 202314.22 ft
16January 27, 197814.02 ft
17January 29, 199413.88 ft
18September 9, 201113.77 ft
19September 25, 197513.47 ft
20January 10, 202413.29 ft
21December 21, 197313.21 ft
22December 12, 199212.97 ft
23May 30, 198412.87 ft
24May 28, 201812.58 ft
25March 11, 199412.58 ft

Most recent crests

  • January 10, 2024: 13.29 ft
  • December 29, 2023: 10.03 ft
  • December 19, 2023: 14.22 ft
  • April 8, 2022: 10.84 ft
  • September 2, 2021: 20.81 ft
  • August 23, 2021: 14.30 ft
  • December 26, 2020: 9.50 ft
  • December 1, 2020: 9.44 ft
  • November 28, 2018: 9.02 ft
  • November 26, 2018: 12.02 ft

Nearby

Upstream, downstream and the gauges around this one.

What this means

Forecasts by the Middle Atlantic River Forecast Center. Forecasts are issued routinely year-round.

Sources

Stage, flood stages, impacts and crest history from NOAA’s National Water Prediction Service. Streamflow and the daily record from the U.S. Geological Survey.