Captain George Vancouver sailed through here in 1792 aboard HMS Discovery, charting the maze of islands and channels that define this stretch of the British Columbia coast. The passage took his ship's name -- or perhaps not directly. Some historical accounts credit Captain Henry Kellett with naming the waterway, reasoning that Vancouver's Discovery had already passed through and the name was applied retrospectively. Either way, the strait has carried the name for more than two centuries, a reminder that European mapping of these waters was messy, overlapping, and often disputed even among the cartographers themselves.

Discovery Passage stretches from the Strait of Georgia at Campbell River to Johnstone Strait at its northern end, with an average width of two kilometres. But the passage is defined by its tightest point: Seymour Narrows, where the channel squeezes to just 750 metres and currents can reach 15 knots. Until 1958, a submerged twin-peaked mountain called Ripple Rock lurked nine feet below the surface here, sinking or badly damaging more than 100 vessels and killing at least 114 people before it was blown apart in one of the largest non-nuclear explosions in history. Even without Ripple Rock, the narrows remain a demanding stretch of water. Vessels time their transit to slack tide, and even experienced captains approach with caution.

The traffic through Discovery Passage is constant and varied. Alaska Marine Highway ferries carry passengers and vehicles between the Pacific Northwest and southeastern Alaska. BC Ferries operates routes connecting Campbell River to Quadra Island, shuttling 18 round trips daily across the southern mouth of the passage. Cruise ships bound for Glacier Bay and Juneau thread through on summer schedules. Cargo ships, tugboats hauling log booms, and fishing vessels heading for the rich grounds of Johnstone Strait all share the same narrow corridor. The passage is, in effect, a two-lane highway of water serving as the only practical route between the sheltered waters of the Salish Sea and the open coast to the north.

Quadra Island forms most of the eastern shoreline of Discovery Passage, its forested slopes rising directly from the water. At the northern end, Sonora Island takes over where Quadra ends, marking the transition into Johnstone Strait. On the western shore, Vancouver Island's coast is anchored by the city of Campbell River, a community of roughly 35,000 that owes much of its identity to the waters at its doorstep. The salmon runs that pass through Discovery Passage have sustained both the We Wai Kai people and the commercial fishing industry for generations, and the city styles itself as the gateway to the northern island -- the last significant settlement before the road runs out and the wilderness begins.