North Branch Raritan River at South Branch, NJ
River level and flood forecast · Somerset County
The river is 5.6 ft below flood stage (8 ft).
The last 7 days and the forecast
NWS forecast issued Sun, Dec 31, 7 PM. Forecasts change as rain falls and as upstream water arrives.
Get flood alerts for this river
An email when the National Weather Service forecasts North Branch Raritan River at South Branch to flood, when it floods, and when it's over.
Flood stages
| Major flood stage | 11 ft |
| Moderate flood stage | 9 ft |
| Flood stage | 8 ft |
| Action stage | 7 ft |
| Record crest (September 2, 2021) | 20.26 ft |
What floods at each level
From the National Weather Service, highest first.
- 11 ftFlooding increases impacting roadways and structures along Milltown Road, North Branch River Road, and Old York Road toward Raritan.
- 9 ftFlooding increases on Old York Road. The road remains closed.
- 8 ftFlooding begins on Old York Road on the west side of the bridge. The road is closed.
- 7 ftThe river leaves it's banks and floods surrounding open land.
Highest crests on record
- 20.26 ft — September 2, 2021
- 18.98 ft — September 16, 1999
- 18 ft — February 6, 1896
- 17.69 ft — August 28, 2011
- 16.45 ft — August 19, 1955
Recent crests: 8.27 ft (March 6, 2026) · 14.28 ft (January 10, 2024) · 11.57 ft (December 28, 2023) · 13.78 ft (December 18, 2023) · 9.24 ft (December 11, 2023)
Up and down the river, and nearby
- UpstreamNorth Branch Raritan River near Raritan, NJ
- South Branch Raritan River at South Branch, NJ
- North Branch Raritan River at North Branch Village, NJ
- Peters Brook at Somerville, NJ
- South Branch Raritan River at Neshanic Station, NJ
- Royce Brook at Hamilton Road, NJ
- Lamington (Black) River at Burnt Mills, NJ
- Raritan River at Manville, NJ
Not an official source. River levels, forecasts, flood stages and impacts are from the National Weather Service (SBRN4); flow from the U.S. Geological Survey. Readings are provisional. In a flood, follow your local officials and the NWS at weather.gov.