C.A. Thayer is a schooner built in 1895 near Eureka, California. The schooner is now preserved at the San Francisco Maritime National Historical Park. She is one of the last survivors of the sailing schooners in the West coast lumber trade to San Francisco from Washington, Oregon, and Northern California. She was designated a National Historic Landmark on 13 November 1966. This ship is used for many class field trips.