Orson Schofield (Old Mountain) Phelps (May 6, 1817 - April 14, 1905) was an early Adirondack guide from Keene Valley. He was not a great guide. Indeed many did not consider him even a good guide. He became a local legend due to publicity by people such as writers Charles Dudley Warner and E. R. Wallace, and photographer Seneca Ray Stoddard. Phelps named many of the Adirondack High Peaks, and cut the first trail up Mount Marcy. Phelps Mountain is named in his honor.