Frank Jay Haynes (October 28, 1853 – March 10, 1921), known as F. Jay or the Professor to almost all that knew him, was a professional photographer, publisher and entrepreneur from Minnesota who played a major role in documenting through photographs, the settlement and early history of the great Northwest. He became both the official photographer of the Northern Pacific Railway and of Yellowstone National Park as well as operating early transportation concessions in the park.