Merrimack River Fishing Guides and Conditions, Massachusetts

About the Merrimack River

The Merrimack is the second largest river in New England, and the Massachusetts reach that anglers fish runs from the New Hampshire line down through Lowell, Lawrence and Haverhill toward the tidewater at Newburyport. It is a working river with an industrial past written into its banks: mill buildings, canal headgates and a series of dams that break the flow into a chain of long impoundments separated by short, fast ledge drops. That structure is exactly what makes the fishing good. Above each dam the water is deep, slow and weedy; below each dam it is broken, rocky and oxygenated.

Smallmouth bass are the strength of the river and hold on every piece of current-broken ledge from Tyngsborough down. Largemouth take over in the coves and backwater sloughs, and northern pike, established in the system for decades now, patrol the weed edges and give the river a genuine trophy fish that most anglers do not expect to find inside a city. Channel catfish are abundant and increasingly targeted at night. The spring anadromous runs are the river’s headline event, with American shad stacking below the Lawrence and Lowell dams from mid-May into June and drawing crowds to the fishways and the tailrace water.

This is a bank and small-boat fishery more than a drift-boat one. Access points cluster around the cities, boat ramps are public and paved, and the practical constraint is not permission but current: dam releases and spring runoff can make the tailrace reaches genuinely dangerous. The Lowell gauge below the Concord River confluence is the reading that matters for anyone planning to be on or near the fast water, and it is the number local anglers quote when they talk about whether the river is fishable.

Access

Lowell - the Bridge Street and Pawtucket Boulevard access points sit closest to the gauge and the Pawtucket Falls tailrace, which is the best-known shad and smallmouth water on the reach.
Lawrence - the boat ramp and riverwalk below the Great Stone Dam give bank access to the tailrace and the fishway viewing area during the spring run.
Tyngsborough boat ramp, off Route 113 - the standard put-in for the slower, wider water upstream of Lowell.
Haverhill and Groveland ramps serve the lower, deeper river where largemouth and pike fishing is strongest.
Riverfront parks in Lowell and Lawrence give continuous public bank access through both downtowns.
The tailrace immediately below any dam is fast, cold and unpredictable when generation starts; treat posted release warnings as binding.
City parking is metered or permit-restricted at several access points, so plan the takeout as carefully as the put-in.

Seasons

Spring: high and cold into April, then the American shad run below the dams from mid-May into June, which is the busiest fishing of the year here.
Summer: low, warm and stable. Smallmouth on the ledges, largemouth in the coves, and good night fishing for channel catfish.
Fall: cooling water pushes bass into the faster water and pike become far more active along the weed edges as vegetation dies back.
Winter: the impoundments ice over in a hard winter and the tailrace stays open. Access is limited and the fast water below the dams is not worth the risk.