Heraklion (Greek: Περιφερειακή ενότητα Ηρακλείου) is one of the four regional units of Crete.

Except for the mountains which receive mild to cool winters unlike northern Greece, the warm to hot Mediterranean climate dominates the regional unit.

Within the Heraklion regional unit's boundaries are a number of significant Neolithic and Minoan settlements, most notably the ancient palace complexes of Knossos and Phaistos.

Important ancient cities are: The regional unit Heraklion is subdivided into 8 municipalities.

These are (number as in the map in the infobox):[6] The Heraklion prefecture (Greek: Νομός Ηρακλείου) was created in 1915, after Crete joined with the rest of Greece.