Merrimack River is the largest river in the eastern part of Massachusetts. It is the approach to the cities of Newburyport and Haverhill and to the towns of Amesbury, Merrimacport, Groveland and Bradford. The river is used by vessels of 6-foot draft at high water up to Haverhill and about 12-foot draft at high water to Newburyport. The head of navigation is at the dam just above Broadway Bridge in Lawrence, 25.7 miles above the mouth. The river is seldom entered for refuge and has virtually no commercial traffic.
The shifting bar at the entrance is usually dangerous to cross in heavy weather. The whole entrance breaks in easterly gales. A lighted fairway whistle buoy, about 1 mile off the jetties, marks the approach.
Newburyport is a city on the south bank of the river, 3 miles above the entrance. Merrimack River Coast Guard Station is on the south side of the river west of the American Yacht Club.
At Newburyport the usual and best anchorage is in the channel about 400 yards below the highway bridge, favoring the north side of the channel and keeping clear of the two charted cable areas. The current is reported to run strongest along the south shore here. The holding ground is good.
The yacht club maintains guest moorings as do many of the service facilities and marinas. Numerous private moorings are maintained off Newburyport under control of the Harbormaster.
Public floats are along the south side of the river at Newburyport, about 0.2 mile west of Merrimack River Coast Guard Station. In 1979, 8 feet was reported alongside the floats. Berthing is under the control of the Newburyport Harbormaster.
U.S. Route 1 highway bridge, which crosses the river at Newburyport, has a bascule span with a clearance of 35 feet. In the open position, the draws overhang the channel above a height of 55 feet. The bridgetender monitors VHF-FM channel 16 and works on channel 13; call sign WQA-806. The railroad bridge immediately westward has a swing span with a clearance of 13 feet. The channel is through the north draw.
