John Muir long has been closely associated with nature and the national parks, and rightly so. If you admire him and his writings, let us point you to a site where you can peruse thousands of his letters, sketches, photos, and journals.
The cache can be found at the Holt-Atherton Special Collections at the University of the Pacific, which took the time to scan in more than 6,500 letters, both those he wrote and those sent to him. The collection spans correspondence from 1856 to 1914. According to the university, "since 1970, Holt-Atherton Special Collections has been the repository for the John Muir Papers. Today, approximately 75% of the extant papers of Muir are housed at the Holt-Atherton Special Collections."
This collection includes "letters ... sent and received by Muir, although the collection also includes some correspondence of selected family members and colleagues. Muir's correspondence offers a unique first-hand perspective on his thoughts and experiences, as well as those of his correspondents, which include many notable figures in scientific, literary, and political circles of the 19th and early 20th centuries. All of the letters include full-text transcriptions that can be searched as well as viewed alongside images of the originals."