Which bay has the highest tidal range in the world?

The Bay of Fundy has the highest tidal range in the world. This funnel-shaped bay lies between New Brunswick and Nova Scotia in eastern Canada, with a small section reaching Maine in the United States. It is an arm of the Gulf of Maine and, ultimately, the Atlantic Ocean.

The bay’s average tidal range is about 16 metres, although the exact height varies with location, lunar conditions, weather, and the shape of the coastline. Its narrowing basin and natural tidal resonance reinforce the incoming and outgoing tides, much like water sloshing in a bathtub at the right rhythm.

Fundy experiences two high tides and two low tides during roughly each 24-hour day. Around 100 billion tonnes of water can move in and out during a half-day tidal cycle—about twice the combined flow of all the world’s rivers over the same period.

A common mix-up is confusing the bay’s tidal range with the world’s highest single water level. The record water level recorded in the bay reached 21.6 metres in October 1869, while the famous tidal range refers to the difference between high and low water.