The largest tidal ranges on Earth are found at the Bay of Fundy in eastern Canada, where the vertical difference between high and low tide regularly reaches 17 meters (about 56 feet). During storm surges, tides there have exceeded 20 meters. But the Bay of Fundy isn’t the only place with dramatic tides. Several other coastal locations around the world experience extreme ranges, all shaped by the same underlying physics: the funneling of ocean water into narrowing bays and inlets at just the right geometry.
Bay of Fundy: The World Record Holder
The Bay of Fundy separates the Canadian provinces of New Brunswick and Nova Scotia, and the most extreme tides occur at Burntcoat Head, near the bay’s inland end. NOAA confirms this as the location of the world’s highest recorded tides. Twice a day, roughly 160 billion tonnes of water flow in and out of the bay.
What makes Fundy special is its shape and size. The bay is long, narrow, and gets progressively shallower toward its head. This geometry creates something called tidal resonance: the natural oscillation period of water sloshing back and forth inside the bay closely matches the roughly 12.4-hour cycle of ocean tides. Think of it like pushing a child on a swing. If you push at just the right interval, the swing goes higher each time. The incoming ocean tide “pushes” the water in the Bay of Fundy at almost exactly the frequency needed to amplify it to extraordinary heights.
Other Locations With Extreme Tides
Ungava Bay, Canada
Ungava Bay, at the northern tip of Quebec, is sometimes cited as a rival to the Bay of Fundy. Tidal ranges there can reach roughly 17 meters as well, and some measurements over the years have put the two locations neck and neck. The scientific consensus, however, still gives the edge to Burntcoat Head in the Bay of Fundy as the site of the single highest recorded tide.
Cook Inlet, Alaska
Cook Inlet, the long arm of water that reaches past Anchorage into south-central Alaska, has some of the most impressive tides in the United States. At Anchor Point, the mean tidal range is about 4.8 meters (nearly 16 feet), with diurnal ranges reaching 5.6 meters (over 18 feet). On strong tide days, high water can exceed 6 meters (about 20 feet) above the chart datum. These large swings create powerful currents that make navigation in Cook Inlet notoriously challenging, especially for smaller vessels.
Bay of Mont Saint-Michel, France
The Bay of Mont Saint-Michel on France’s Normandy coast has the second-largest tidal range in Europe. Average tides swing between 10 and 11 meters, but during equinox spring tides the range can hit 16 meters (about 52 feet). The bay is extremely flat and shallow, so when the tide comes in, it advances across the sand flats remarkably fast. This is what makes the famous island abbey of Mont Saint-Michel appear to transform from a landlocked hill to a true island and back again in a matter of hours.
Severn Estuary, United Kingdom
The Severn Estuary, between England and Wales, holds the largest tidal range in the UK, with spring tides reaching around 14 to 15 meters. Like the Bay of Fundy, the estuary narrows and shallows dramatically as it moves inland, concentrating tidal energy into a smaller and smaller cross-section. The effect is strong enough to produce the Severn Bore, a tidal wave that travels upstream along the River Severn and attracts surfers from around the world.
Why These Locations Share Common Features
Extreme tidal ranges aren’t random. They cluster in places with a specific combination of geography. The key ingredients are a wide continental shelf that allows the ocean tide to build momentum, a funnel-shaped bay or estuary that compresses the incoming water, and a basin length that creates resonance with the tidal cycle. Most of these hotspots sit between 50°N and 70°N latitude, where continental shelves tend to be especially wide and coastal embayments are common.
The Coriolis effect, caused by Earth’s rotation, also plays a role at higher latitudes. It pushes the tidal wave more firmly against the shoreline, concentrating the range close to the coast rather than spreading it across open water. This is one reason why tidal ranges measured at shore stations in these regions can be so much larger than what you’d observe offshore.
Polar regions, by contrast, tend to have small tides despite being at high latitudes. The Arctic Ocean is too small to generate its own significant tide and has only a narrow connection to the Atlantic. Antarctica has deep, narrow continental shelves that don’t amplify tidal waves. There are exceptions: thick floating ice shelves can actually increase local tidal ranges by squeezing water flow beneath them into a smaller cross-section.
Spring Tides vs. Neap Tides
The tidal range at any location isn’t constant. It cycles between larger spring tides and smaller neap tides roughly every two weeks. Spring tides happen when the sun and moon align (during full and new moons), combining their gravitational pull. Neap tides occur at the quarter moons, when the sun and moon pull at right angles and partially cancel each other out.
The difference is substantial. In a typical high-range location, spring tide high water might reach 6.5 feet while neap tide high water only reaches about 4.8 feet. Low water drops correspondingly lower during springs (as low as 0.2 feet) compared to neaps (around 1.5 feet). In the Bay of Fundy, this means the already enormous range grows even larger during spring tides, and peaks again during equinox springs in March and September, when the sun is directly over the equator and its tidal pull is strongest.
If you’re planning to visit any of these locations to witness extreme tides, timing your trip around a spring tide, especially near an equinox, will give you the most dramatic show. Tide tables for specific stations are freely available through NOAA and equivalent national agencies.