Jenner, also known as Jenner-by-the-Sea, is a small coastal town and census-designated place in Sonoma County, California, United States, with a population of 122 per the 2020 Census. It is located on the Pacific coast near the mouth of the Russian River. State Route 1 runs through the town and State Route 116 runs nearby, along the Russian River. Immediately south of Jenner is Goat Rock Beach, a unit within the Sonoma Coast State Beach.