Harvard Classics: Two Years Before the Mast and Twenty-four Years After: Text of the book, with search function.
Richard Henry Dana: Chapter 14 of the book "Time of the Bells" by Richard F. Pourade focuses on Dana's experiences in San Diego.
Richard Henry Dana Brief: Legal brief, written by Dana in 1868, concerning the plans to try Jefferson Davis for treason.
Richard Henry Dana, Jr.: Bibliography of Dana writings, speeches, correspondence, and biographies.
Richard Henry Dana, Jr., 1815-1882: Biographical essay by Homer Eaton Keyes, B.L., Assistant Professor of Art in Dartmouth College.
Seventy-Six Years After: As a section in a later edition of "Two Years Before the Mast," the author's son compares the California of his father's time with the California of 1911; provides updated information about the fate of the vessels and people mentioned in the book; and gives biographical information about his father.
Two Years Before the Mast, and Twenty-four Years After: The text of the book, including footnotes, available either by chapter or with the entire book as one file.
Wikipedia: Richard Henry Dana, Jr.: Includes biographical material and a list of selected works.