Ogam var et alfabet som primært blev anvendt til at repræsentere Gæliske sprog. Det ser ud til at have haft sin højeste blomstring i 5.–6. århundrede. Ogam-inskriptioner på monumenter (helleristninger) er blevet fundet i Irland, Skotland, Wales, England og Isle of Man, hvor det primært er blevet anvendt som territorielle markeringer.

Ogam-alfabetet består af 25 bogstaver. De første 20 bogstaver (feda) anses for at være primære, mens de sidste 5 (forfeda) anses for at være supplerende.

• Runealfabet
• Druide
• Amerika

• The Ogham Alphabet with variant names of the letters, and names of the associated plants Arkiveret 4. februar 2005 hos Wayback Machine
• Every Ogham Thing on the Web
• Celtic Ogham Arkiveret 21. oktober 2006 hos Wayback Machine – by Curtis Clark
• Cult Archaeology Strikes Again: A Case for Pre-Columbian Irishmen in the Mountain State? By W. Hunter Lesser. West Virginia Archeologist Volume 35, Number 2. 1983 WV Archeology Society Arkiveret 28. oktober 2014 hos Wayback Machine Citat: "...the only accepted case of pre-Columbian European contact in North America is the Norse site of L'Anse aux Meadows in northern Newfoundland, dated about A.D. 1000. Most significantly, there is not a single case of European artifacts dating from pre-Norse times, despite the tremendous amount of archeological work done on this continent (Goddard and Fitzhugh 1978: 9; Morison 1971)...."
  • Kontroversiel (omfattende): European bronze age visitors in America e.legner@ucr.edu
    • European bronze age visitors in America e.legner@ucr.edu: Introduction Citat: "...Nevertheless, there is considerable evidence of a voyage or voyages of a Bronze Age Scandinavian king, Woden-lithi, to North America around 1700 BC from texts found inscribed in the rocks at Peterborough, Ontario, Canada (Figs. 18 & 19 & MAP), and other North American sites...One alphabet, "ogam consaine" was employed by the ancient peoples of Ireland and Scotland (often erroneously referred to as Celts..."
    • Archeology, Epigraphy, Pre-Columbian Contacts in America e.legner@ucr.edu
  • Kontroversiel: Science Frontiers ONLINE. No. 27: May-Jun 1983: Ogham inscriptions in west virginia? Citat: "...Based upon the style of the Ogham, these petroglyphs may have been chiseled some time between the early Sixth and late Eighth centuries. The Ogham writers may have been Irish monks who, after the fashion of St. Brendan, sailed west from Europe during this period..."
  • The mystery stone of Beverly, Kansas Citat: "....The epigrapher used an Ogham script of hieroglyphics and Iberian-punic characters to interpret the inscription. If he is correct, then the stone dates before the Latin alphabet and Spanish language, over 2000 years ago..."