Guerneville is built adjacent to the Russian River. Redwoods grew in the riverbed with such vigor that just a few centuries ago, the valley had the greatest biomass density on the planet, according to local lore. The local Pomo Indians used the area as a summer camp and called it "Ceola" ( or "cee-oh-lay") which meant "shady place." Except for a large stand of ancient trees preserved in the Fife Creek watershed, now the centerpiece of Armstrong Woods Park, many of the trees were logged in the late 19th century and the early 20th century, giving rise to the first English name for the place – "Stumptown." Logging in the area boomed after vast amounts of lumber were needed for rebuilding after the 1906 earthquake. The annual town parade still commemorates the old place name by calling itself "Stumptown Days." The present name Guerneville was introduced to honor Swiss immigrant George Guerne, a local businessman of the 19th century who owned the town's sawmill. By 1870, there was a U.S. Post Office in Guerneville; it was listed by the name "Guerneville". Although locals may be found selling T-shirts that say "Don't call it Guerneyville", many have called the town "Guerneyville" in spelling and pronunciation since the 1800s. The extensive redwood forests on the surrounding mountains are less than 200 years old, having been replacement plantings for much of the logging done in the 19th century.