The Avenue of the Giants Marathon is held annually in May along the Avenue of the Giants in Humboldt Redwoods State Park in Humboldt County, California, United States.
The course, consisting of two out-and-back legs, is almost entirely under the canopy of redwood trees.
Half marathon and 10K races are run concurrently.
A sister event, the Humboldt Redwoods Marathon, is run in October over the same course.
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