River traffic. Piscataqua River currents restrict travel by tankers and other large vessels to slack tide, roughly four hours a day. See chart below for slack tide at the entrance to Portsmouth Harbor. The entrance is nearly three miles from the location of the PortsmouthNH.com's HarborCam. Slack tide at the Harbor Cam is roughly a half hour later. A schedule of shipping in the Piscataqua is not available.
Currents. The swift currents of the Piscataqua River make Portsmouth Harbor one of the fastest flowing tidal waterways in the Continental United States (NOAA list of 50 fastest in North America). The ice-free deep-water channel has been used for shipping since the 1600s.
Piscataqua River Currents|
Tue 12:09am EST Moonset
Tue 12:37am EST 0.00 knots Slack, Flood Begins
Tue 02:39am EST 1.31 knots Max Flood
Tue 06:38am EST -0.00 knots Slack, Ebb Begins
Tue 07:03am EST Sunrise
Tue 09:18am EST -1.81 knots Max Ebb
Tue 12:15pm EST Moonrise
Tue 01:11pm EST 0.00 knots Slack, Flood Begins
Tue 03:01pm EST 1.06 knots Max Flood
Tue 04:07pm EST Sunset
Tue 06:52pm EST -0.00 knots Slack, Ebb Begins
Tue 09:40pm EST -1.91 knots Max Ebb
Wed 01:14am EST Moonset
Wed 01:35am EST 0.00 knots Slack, Flood Begins
Wed 03:36am EST 1.21 knots Max Flood
Wed 07:04am EST Sunrise
Wed 07:38am EST -0.00 knots Slack, Ebb Begins
Wed 10:25am EST -1.76 knots Max Ebb
Wed 12:45pm EST Moonrise
Wed 02:14pm EST 0.00 knots Slack, Flood Begins
Wed 04:02pm EST 0.91 knots Max Flood
Wed 04:07pm EST Sunset
Wed 07:54pm EST -0.00 knots Slack, Ebb Begins
Wed 10:42pm EST -1.78 knots Max Ebb
About the Piscataqua River. This Piscataqua River is a 13-mile long tidal estuary formed by merging of the Salmon and Cocheco rivers. The river, which separates Maine and New Hampshire, also drains Great Bay, a National Estuarine Research Reserve site. The last 8.8 miles of the Piscataqua River constitute Portsmouth Harbor, which stretches across New Castle, Portsmouth, and Newington, and the Maine communities of Kittery and Eliot.
New Hampshire-Maine border. The N.H.-Maine border lies in the middle of the Piscataqua River. Its exact location was the subject of a long-running dispute settled by the U.S. Supreme Court.
What kind of name is Piscataqua (pis-cat-a-qua)? Easy for you to say, but not so easy to spell. See an extended examination of the origin of the word at SeacoastNH.com and 20 ways to spell Piscataqua.
More information. For more about the Piscataqua River, see the Army Corps of Engineers Water Resources web page.