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

The regional unit of Heraklion borders on the regional units of Rethymno to the west and Lasithi to the east. Farmlands are situated in the central and the northern parts, at the coast and in valleys. The mountains dominate the rest of the regional unit, notably the south. The main mountains are parts of Ida or Idi Mountains to the west and Asterousia in the south. The regional unit includes the island of Dia to the north.

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. While both archaeological sites evince Neolithic habitation from 7000 BC, it is the rich finds of Minoan civilisation, which flourished approximately 2800 to 1450 BC, that command the greatest scholarly attention.

Important ancient cities are:

• Knossos
• Phaistos
• Hagia Triada
• Kommos
• Gortys
• Tylissos
• Malia
• Lyttos
• Amnisos
• Kaloi Limenes

Historical population

Year	Pop.	±%
1991	265,708	—
2001	291,225	+9.6%
2011	305,490	+4.9%
2021	305,017	−0.2%

The regional unit Heraklion is subdivided into 8 municipalities. These are (number as in the map in the infobox):

• Archanes-Asterousia (2)
• Faistos (7)
• Gortyna (4)
• Heraklion (Irakleio, 1)
• Hersonissos (Chersonisos, 8)
• Malevizi (5)
• Minoa Pediada (6)
• Viannos (3)

The Heraklion prefecture (Greek: Νομός Ηρακλείου) was created in 1915, after Crete joined with the rest of Greece. As a part of the 2011 Kallikratis government reform, the regional unit Heraklion was created out of the former prefecture Heraklion. The prefecture had the same territory as the present regional unit. At the same time, the municipalities were reorganised, according to the table below.

New municipality	Old municipalities	Seat
Archanes-Asterousia	Archanes	Peza
	Asterousia
	Nikos Kazantzakis
Faistos	Zaros	Moires
	Moires
	Tympaki
Gortyna	Gortyna	Agioi Deka
	Agia Varvara
	Kofinas
	Rouvas
Heraklion (Irakleio)	Heraklion	Heraklion
	Gorgolainis
	Nea Alikarnassos
	Paliani
	Temenos
Hersonissos (Chersonisos)	Hersonissos	Gournes
	Episkopi
	Gouves
	Malia
Malevizi	Gazi	Gazi
	Krousonas
	Tylisos
Minoa Pediada	Arkalochori	Evangelismos
	Thrapsano
	Kasteli
Viannos	Viannos	Ano Viannos

• Province of Pyrgiotissa - Voroi
• Province of Kainourgio - Moires
• Province of Malevizi - Agios Myronas
• Province of Temenos - Heraklion
• Province of Pediada - Kasteli
• Province of Monofatsi - Pyrgos
• Province of Viannos - Pefkos

Note: Provinces no longer hold any legal status in Greece.

• GR-90/E65
• GR-97
• GR-99

• El Greco (medieval Castilian nickname meaning "the Greek"), by which Δομήνικος Θεοτοκόπουλος Domênikos Theotokópoulos, is best known. (Born 1541, Fodele, Heraklion and died on April 7, 1614, Toledo, Spain), a world-famous painter, sculptor and architect
• Nikos Kazantzakis was born in the village Varvaro (renamed to Myrtia in 1965) The municipal unit in which Myrtia is located, was named after him.

The following television channels serve the prefecture:

• Creta Channel
• Kriti TV

• List of settlements in the Heraklion regional unit

• Arthur J. Evans, (1921–35) The Palace of Minos, volumes 1-4
• C. Michael Hogan, Knossos fieldnotes, Modern Antiquarian (2007)
• Ian Swindale, Phaistos, Minoan Crete Retrieved 13 May 2013.

• Monuments in the prefecture of Heraklion