Great! You’ll find a wide variety of experiences and environments—ranging from lake-like calm water to fierce (and sometimes dangerous) rapids and tidal flows.
NOTE: for links to public boat ramp websites, please scroll down.
Here is information on each of the four major regions of the Merrimack:
Lower Mass.: From the sea to the Great Stone Dam in Lawrence, 30 miles. Most of this stretch is tidal, which can present challenges for paddlers—particularly when the tide is going out. This is the busiest stretch of the river, with thousands of power boats docked at marinas, resting on moorings, or entering via boat ramps. Many miles of excellent water for powerboating. Some kayaking happens along this part of the river, but in many areas you’ll contend with wakes and confusing currents.
Upper Mass.: From the Great Stone Dam in Lawrence to the New Hampshire border, 19 miles. A wide variety of boating options (kayaks, canoes, power boats, crew boats). This region has 2 dams—in Lawrence and Lowell.
Lower N.H.: From the Mass. border to Garvin’s Falls dam in Bow, 35 miles. This area also supports a good variety of boating options, though it can be shallow and tricky in some parts. Not an ideal place to bring a deep-draft boat. There are 3 dams—in Manchester, Hooksett and Bow.
Upper N.H.: From Bow to the river's headwaters, in Franklin—30 miles. This is the arguably the best region for paddlers. A wide range of water conditions (ranging from calm to rapids). Long stretches of wild, unpeopled shorelines, this area is eligible for inclusion on the national list of Wild and Scenic Rivers. Tends to be shallow and rocky in many spots.
Kayaking on the Merrimack River in Lower Massachusetts
Of the 4 regions of the Merrimack, this is the trickiest, requiring you to not only have good-to-excellent paddling skills, but also a thorough understanding of tidal impacts.
Most of this stretch—particularly from Haverhill to the river mouth at Salisbury/ Newburyport—is tidal. For kayakers, that poses a logistical challenge. Keep in mind that the lower Merrimack is a powerful river along which billions of gallons of water flow every day. The river current, pushed along by the tide, can be so strong that it’s impossible to make headway against it. Your best bet is to time your trip to the period around the turn of the tide —whether high tide or low tide. Ideally, you’ll literally be riding the tide and letting it push you toward your destination, at which point you can turn around and let it pull you back to your launch site.
For example, if you are launching in Newburyport and plan to take a 3-hour trip, you’ll want to push off 1.5 hours before high tide or low tide. If before high tide, go upstream 1.5 hours, then turn around and head back to your launch site. If before low tide, head downstream for 1.5 hours, then turn around. This will make for a much more enjoyable trip.
And here’s an important piece of information to remember: As you progress up the river, the time at which the tide changes direction gets later—by up to an hour or more. So, for example, if you're looking at a tide chart that says high tide will occur at 1 p.m. at Plum Island, it means that high tide at Amesbury will be closer to 2 p.m., and perhaps 2:30 p.m. at Haverhill.
Tides are tricky to master. If you want to take a deeper dive into understanding them, look at the tide height on a tide chart. The tide doesn’t rise and fall at the same height every day. Due to the location of the moon, the tide may rise a few feet higher (or lower) than normal on some days. This will affect the speed and power of the water you encounter on the river.
Lower Merrimack areas of caution
There are three areas we’d like to point out as potentially hazardous on the tidal Lower Merrimack.
Chain Bridge, Amesbury/Newburyport: This historic bridge, connecting the south side of Deer Island to Newburyport, has a nasty surprise lurking underneath it when the tide is going out. Often there’s a dangerously large standing wave and trench here, caused by the great gouts of water surging downstream. It feels like rapids. To avoid it, pass under the Hines Bridge, which is located on the northern side of Deer Island.
Boat slips, Newburyport: In Newburyport you’ll encounter several marinas that have boat slips (i.e., floating docks) extending 200-300 yards into the Merrimack. You’ll want to navigate in the main channel here—steer clear of those slips, don’t be tempted to try to follow close to the shoreline. It’s impossible to navigate under the boat slip walkways. If you wander into the marina areas, there’s a good chance you'll get caught on a dock and capsize.
River mouth, between Salisbury Beach and Plum Island: You should never attempt to navigate a kayak or paddle-dependent craft in the mouth of the river, which we define as the area between Salisbury Beach State Reservation and Plum Island. The Merrimack is particularly powerful and unpredictable here—hence, this is the most common site of drownings and mishaps along the river.
The biggest boat ramp (in terms of parking spaces) on the Merrimack is at Cashman Park in Newburyport. Here are the details.
Indian River: Located in West Newbury, the Indian River is an oversized creek that runs through a rare freshwater marsh. This is a beautiful stretch of waterway, calm and peaceful.
The “Back River”: Running along the north side of Deer, Eagle, Carr and Ram islands (shown in the adjacent map) is a long stretch of the Merrimack known as the “back river.” It’s shallow and somewhat rocky, which discourages the vast majority of motor boaters from navigating it. Also, the main channel runs along the south side of these islands, another reason that motor boats avoid the area. What you’ll find here is an almost “in the wild” experience. Nearly totally devoid of homes, the shoreline features several tidal creeks that you can explore. And you can land on the islands (they're owned by the state) and roam around. Of particular interest is Carr Island, the site of a ferry dating from the mid-1600s. There, you will come upon centuries-old ruins. Also of note is High Rock, a local hangout popular with teens who enjoy leaping into the river. All in all, the Back River route is a welcome respite from the busy harbor feel of Newburyport's waterfront.
Joppa Flats/Woodbridge Island: Just downstream of Newburyport’s bustling waterfront, the Merrimack changes dramatically. It widens to roughly a mile, then narrows again at the mouth, before flowing furiously into the sea. This wide stretch is worth exploring, though it’s best to do so around high tide, close to a shoreline. On its southern side lies Woodbridge Island, which contains an interesting stretch of marshland surrounded by tidal waterways. This also is where you enter the Plum Island River as you navigate along the backside of the island.
Plum Island Basin and Hump Sands: Just upstream of Plum Island you'll find an interesting sandbar called Hump Sands. It lies about a quarter mile west (upstream) of Plum Island’s northern tip, roughly in the middle of the Merrimack. It's exposed at low water, making for a refreshing place to pull up your boat and wade in the tidal wash of the river. At Plum Island’s northern end you’ll also find the entrance to The Basin, the remains of an ancient channel that once served as the main course of the Merrimack. Now it's a calm tidal waterway extending about a mile. A visit there feels like paddling in a millpond.
Enjoy your adventure!
MRWC Staff and Board