Beacon Rock is an 848-foot-tall (258 m) monolith composed of basalt on the north bank of the Columbia River. It was named by Lewis and Clark in 1805; they originally referred to it as Beaten Rock, later as Beacon Rock. They noted that the rock marked the eastern extent of the tidal influence in the Columbia. The rock was later known as Castle Rock, until 1915 when its name was changed back to Beacon Rock.
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