Lassithi is the easternmost prefecture of Crete. On three sides of Lasithi surrounded by sea: the Cretan Sea from the north, east and Carpathian Libyan south. West is Heraklion naturally limit the Sierra Dikti. Capital of Lassithi is Agios Nikolaos, which is built on the ancient city of Lato on the northwestern part of the larger Gulf of Crete, graphic Mirampelou.

The terrain is mostly mountainous, with Mount Dikti (or Lassithi mountains) that dominates the county boundaries of Heraklion and Lassithi, occupy entirely the province of Lasithi provinces and part of Mirabello and Ierapetra. A second mountain, the Steiako Mountains, located east of the county. There are two plateaus, the most famous Lassithi plateau Net (DD Kritsa in the Municipality of Agios Nikolaos).