Merrimack River at Nashua, NH

Hillsborough County, New Hampshire · USGS gauge 01096508 · NWS NSHN3 · Merrimack River flood status · New Hampshire river levels

Is Merrimack River at Nashua, NH flooding right now?

Merrimack River at Nashua, NH measured 4.63 ft on 2026-09-11 01:15:00 UTC. That observation was 13.4 ft below its 18 ft flood stage. This is the latest available reading, not a guarantee of current conditions.

Gauge height

4.63 ft

as of 76 min ago

Streamflow

2,580 cfs

data refreshed 13 min ago

Minor flooding here begins at 18 ft, with major flooding at 35 ft. The highest crest on record was 41.3 ft on Fri, Mar 20, 1936.

Flood forecast

NWS forecast, issued 11 hours ago. Forecasts are issued for select river points and update through the day.

Flood stages at this gauge

Category	Stage	Current distance
Action	16 ft	11.4 ft below
Minor flood	18 ft	13.4 ft below
Moderate flood	26 ft	21.4 ft below
Major flood	35 ft	30.4 ft below

New to these numbers? What does flood stage mean? · How to read a river gauge · Why is the river rising?

Highest crests on record

Stage	Date
41.3 ft	1936-03-20
30.5 ft	1938-09-23
26 ft	2006-05-15
23.5 ft	2007-04-17
22.4 ft	1987-04-07

Last 7 days

Past 7 days · 4.49–4.77 ft

Nearby gauges

Gauge	Distance	County
Beaver Brook at North Pelham, NH	4.7 mi	Rockingham County
Souhegan River at Merrimack, NH	7.2 mi	Hillsborough County
Nissitissit River at Pepperell, MA	9.3 mi	Middlesex County
Nashua River at East Pepperell, MA	9.4 mi	Middlesex County
Merrimack River below Concord River at Lowell, MA	10.9 mi	Middlesex County

Provisional data: Real-time readings are provisional and subject to revision by the USGS — sensors can be affected by ice, debris, or equipment malfunction. Do not rely on this site for decisions involving personal safety; follow official guidance from the National Weather Service and local authorities.

Sources: USGS monitoring location · NWS gauge & forecast