Frog Woman Rock is a volcanic monolith in the Russian River canyon in Mendocino County, where geology, transportation history, Native tradition, and recreation converge. An active earthflow, the Pieta Rock Slide, presses the river against the rock and helps create dangerous rapids, making this a notable whitewater stretch. The canyon long served as a route between Ukiah Valley and Bay Area seaports, with a railroad tunnel driven through the rock in 1889 and east-side wagon roads later becoming Highway 101. Once widely known by an older name tied to a debated printed legend, the site was later recognized through Pomo traditions as the dwelling of Frog Woman, and its official name was changed in 2011 to reflect that heritage.