Harrye Rebecca Piper Forbes (nee Smith; May 6, 1861 – September 18, 1951), also known as Mrs. A. S. C. Forbes, was an American historical preservationist, journalist, and author, best known for her efforts to preserve and promote California's El Camino Real and the old Spanish missions which it connected. She was for many years director of the Historical Society of Southern California. Forbes was a writer on topics such as the history of California, and Native Americans, and the Boxer Rebellion in China. She sometimes used the pseudonym "Harry Forbes".