Ginkgo Petrified Forest State Park at Vantage preserves a major concentration of petrified wood from a Miocene landscape about 15.5 million years old, when central Washington was wetter and forested by dozens of tree species. Buried in volcanic ash, the trees gradually turned to stone, then were later exposed by erosion after basalt flows had protected them. The area was also long home to the Wanapum people, who lived along the Columbia shoreline and left hundreds of petroglyphs. Modern excavation began after discoveries around 1927, and the park opened in 1938. Later dam construction altered the landscape, but the site remains important for fossil exhibits, salvaged petroglyphs, and recreation.