The Library of Tarchamus was a secret library hidden deep inside a mountain in ancient Netheril in a location a few days journey from present day Everlund. The library was built by the legendary arcanist Tarchamus the Unyielding both as a repository for his knowledge and as a trap for his Netherese rivals. Many Netherese arcanists fell victim to traps or Tarchamus' mummy while searching the library for his secrets.
The library had three levels and was said to have housed over 100,000 volumes. The central level had a huge domed ceiling and was lit by mage lights. 120 bookcases radiated out from the center of this level. The lower level contained a pit where Tarchamus' mummy resided as well as air vents which could be used as an escape route. Powerful wards were placed throughout the library to prevent scrying. There were also traps, although most were illusions.
The library was inhabited by the ghosts of Tarchamus' apprentices as well as Tarchamus' mummy. Additionally, the Book of Tarchamus, which contained Tarchamus' consciousness, sat on a pedestal in the central area on the second level.
The library was hidden deep inside a mountain a few days from Everlund. A series of caves led to the library's entrance. The outer cave's entrance was located in the side of a cliff and contained a colony of Fungus men. The second cave contained a large lake. An underwater stream, believed to originate in the Underdark led to the entrance to the actual library.