A resort on the east shore of East Sound at the head of Cascade Bay. It was founded by Andrew Newhall in 1890 as a saw mill named the Cascade Lumber Company. At that time, the post office was named Newhall. In 1905, Robert Moran, a prominent ship builder, bought Newhall’s interest and on June 15, 1906, he changed the name to its present form. Moran built an estate, which continues to be a showplace. The name was taken from Rosario Strait.

Once a show-place of the islands, where visitors were welcomed, this 1,800-acre estate with its low, stone mansion was sold by its owner in 1938.

Today, the Arts & Crafts-style mansion, completed in 1909 for Moran and his family, serves as a resort and spa. Regularly scheduled lectures held in the music room chronicle the history of the estate.