Where are the biggest tides in the world?

The Bay of Fundy between Nova Scotia and New Brunswick, Canada, where the range between low and high water reaches about 52 feet (16 meters) at Burntcoat Head — the largest tidal range on Earth.

Where are the biggest tides in the United States?

Alaska's Cook Inlet. Turnagain Arm near Anchorage sees ranges around 33–40 feet, and Anchorage itself swings 26–30 feet between low and high tide. Outside Alaska, the U.S. champion is Eastport, Maine at roughly 18–20 feet.

Why are tides so much bigger in some places?

Three ingredients: a coastline shaped like a funnel that concentrates the water, a shallowing seabed that stacks it higher, and — the secret sauce — resonance, when the natural sloshing period of the bay matches the 12.4-hour tidal rhythm so every tide reinforces the last.

TimeAndSpace.Science

The Biggest Tides in the World

From Canada's 52-foot monster to Alaska's rideable bore tide — where the ocean swings hardest, why it happens there, and live charts for every U.S. giant.

⚠ Warning: NOAA astronomical tide predictions only — not for navigation or safety decisions. For those, check NOAA and the U.S. Coast Guard. Use at your own risk — Terms.

The world leaderboard

Bay of Fundy — Burntcoat Head, Nova Scotia, Canada

up to ~52 ft (16 m). The world record. The bay's length makes it resonate almost perfectly with the 12.4-hour tidal rhythm, so each tide amplifies the last — 100+ billion tons of water move in and out twice a day.

Ungava Bay, Quebec, Canada

~50 ft (15+ m). Fundy's near-twin in the Canadian Arctic and, by some surveys, its equal.

Severn Estuary / Bristol Channel, UK

~48 ft (14–15 m). Europe's biggest — the funnel shape squeezes the Atlantic tide into a famous river bore surfers ride upstream.

Bay of Mont-Saint-Michel, France

~46 ft (14 m). The tide crosses miles of flats — legend says it returns 'at the speed of a galloping horse.'

Río Gallegos, Argentina

~43 ft (13 m). South America's largest, at Patagonia's Atlantic edge.

Turnagain Arm, Cook Inlet, Alaska — U.S. #1

~40 ft (12 m). America's giant, with a rideable bore tide. See it live at the nearby stations below.

Ranges are approximate spring-tide maxima from published oceanographic surveys; exact figures vary by measurement point and year.

Watch America's giants live

Every U.S. entry has a live NOAA chart here: Anchorage, AK (26–30 ft, the closest station to Turnagain Arm) and Nikiski, AK in Cook Inlet; Southeast Alaska's Skagway, AK, Juneau, AK and Ketchikan, AK (15–20+ ft); and the East Coast champion Eastport, ME (~18–20 ft), just across the border from the Bay of Fundy itself. For the opposite extreme, compare the Gulf's tiny tides at Galveston, TX or Pensacola, FL — often barely a foot.

Why these places?

Open-ocean tides are only about 2 feet. The giants happen where geography amplifies them: a funnel-shaped bay concentrates the incoming water, a shallowing bottom forces it upward, and resonance — a bay whose natural slosh matches the 12.4-hour lunar rhythm — makes each tide push the next like a hand timing shoves on a playground swing. The Bay of Fundy nails all three.

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