09/02/2026
You'll hear that rafting Grand Canyon is 277 miles. That's correct. It's also not the whole story.
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Start above it all. Below Glen Canyon Dam there's about fifteen miles of smooth water down to Lees Ferry. That stretch is still Glen Canyon, managed as a national recreation area rather than the park, and there isn't a rapid in it. If you take the float trip out of Page, that's where you are β not in Grand Canyon.
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Lees Ferry is river mile zero. Every trip launches there, because it's the only place for hundreds of miles you can get a boat down to the water.
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From Lees Ferry you're in Marble Canyon. Its own canyon, its own name, and for six years its own national monument β Lyndon Johnson designated it in 1969, largely to block dams that had been proposed for that stretch of river.
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Marble runs 61.5 miles to the confluence with the Little Colorado. That's where Grand Canyon proper begins, geologically speaking.
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So where does 277 come from? On January 3rd, 1975, Gerald Ford signed the Grand Canyon National Park Enlargement Act. It abolished the Marble Canyon monument, folded it into the park, and doubled the park to 1.2 million acres β defining it as running from the mouth of the Paria River, which is Lees Ferry, all the way to the Grand Wash Cliffs.
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277 river miles.
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Both answers are right. Geology says one thing. Congress said another.
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Fixin' to visit canyon country? π€ Comment CHEAT and I'll send over my free Grand Canyon Cheat Sheets β handy if you want to see the rims before you get on that water.