The world's largest collection of material relating to Sir Arthur Conan Doyle and Sherlock Holmes is held by Portsmouth City Council and displayed in part inside the Portsmouth Museum on Museum Road. The collection — donated by collector Richard Lancelyn Green — includes first editions, manuscripts, illustrations, posters, and Doyle's own personal items.
A permanent gallery titled "A Study in Sherlock" walks you through Doyle's Portsmouth years and his creation of the great detective. Free with general museum entry.