Walking the Northern Canal

The normal operating (open) season for the Northern Canal Walkway is from May 15-October 15. During the operating season, and subject to waterflow and construction limitations, the walkway is open from 9 a.m. - 5 p.m.

During the summer months, visitors can experience one of the great marvels of mid-19th-century American engineering- the Northern Canal. Finished in 1847, the Northern Canal runs along the Merrimack River separated by a 36 foot high granite wall later named the "Great River Wall."

The Northern Canal Walkway (which includes the Great River Wall) provides breathtaking views of the Merrimack River, the canal and the surrounding areas.

For the Northern Canal Walkway to be open, the flow rate of the Merrimack river must be below 3500 cubic feet of water per second (ft3/s). The decision to open or close the walkway for the day is based on the flow rate at 9 a.m. each morning.

To check the flowrate of the Merrimack River, please visit the USGS flowrates page. Below the graph, find the “Latest value” column. You can also toggle the indicator to the far right of the chart and read the current rate listed above the chart.

In this example, the flow rate is indicated at 8610 ft3/s - which is higher than the 3,500 ft3/s maximum for the Northern Canal Walkway to be open, so the walkway would be closed on this day.

Though the USGS updates flow rates minute by minute, the decision is made to open or close the walkway for the day based on the flow rate at 9 a.m. each morning.

For any questions, please call us at (978) 970-5000.