Valley of the Giants, Forest preserve in Oregon Coast Range, United States.

Valley of the Giants is a 51-acre (21 ha) forest preserve in a remote part of the Oregon Coast Range near the former company town of Valsetz, managed by the Bureau of Land Management. It holds large specimens of Douglas-fir and western hemlock, and receives more than 180 inches (4,600 mm) of rain a year.

The Bureau of Land Management designated the 51-acre site an Outstanding Natural Area in 1976. Before "Big Guy", a Douglas-fir estimated at over 600 years old, 230 feet tall and 36.5 feet in girth, was blown down by a wind storm in 1981, it ranked as the second largest known standing Douglas-fir in Oregon. On June 6, 2008, the Oregon Heritage Tree Program dedicated the area as a Heritage Tree Grove.

On June 6, 2008, the Oregon Heritage Tree Program dedicated the Valley of the Giants Outstanding Natural Area as a Heritage Tree Grove. The designation covers the grove of large Douglas-firs and Western Hemlocks, including the site of "Big Guy", the Douglas-fir blown down in 1981 that was then the second-largest known in Oregon.

The site sits west of Falls City and access is via forest roads that vary with the season and weather conditions. Check current conditions with the Bureau of Land Management before visiting, as heavy rain can make roads impassable.

Before it fell in a 1981 windstorm, the Douglas-fir known as "Big Guy" was estimated at over 600 years old, roughly 230 feet tall and 36.5 feet around, then the second-largest Douglas-fir known standing in Oregon.