|Elevation:||2,410 m (7,900 ft) (Agios Ilias)|
|Location:||eastcentral Attica about 15 km E of Athens|
|Length:||approx. 15 to 20 km, north to south|
approx. from 5 to 7 km from east to west
|Easiest route:||climb, road|
Hymettus, also Hymettos (Gr. Υμηττός, phonetic spelling Imitós) is a mountain range in Athens Area, East Central Greece. It is also colloquially known as Trellos or Trellovouno (crazy mountain), probably because of its propensity to change colors under shifting sunlight. The height is 1,026 m at Evzonas and the length is 16 km (10 mi) between Athens and the Saronic Gulf and 6 to 7 km from east to west. It was noted for its thyme honey. Marble has been quarried since antiquity. The neighboring communities that surround the mountain are Athens, Zografou, Kaisariani, Vyronas, Ilissia, Helioupolis, Elliniko, Glyfada, Voula and Vouliagmeni in the west, Varkiza, Vari, Markopoulo and Paeania to its east, and Papagou, Aghia Paraskevi, Gerakas and Glyka Nera. Most of the forest is in the north, and much of the mountain is rocky, deforested, grassy and made out of limestone.
Major campuses of the Athens University and the National Technical University (collectively called "University Town") are located on the west-facing slope, between the newly-built "Hymettus Ring", a ring road connencted with the Attiki Odos freeway with five interchanges beginning with Y and are filled with tunnels, and the Athens urban sprawl. A transmitter park for all major TV and radio stations is located at the top of the mountain. Urban housing almost surrounds the entire mountain range. Access to the top of the mountain are restricted to authorized vehicles for the towers
Almost all of Athens, eastern suburbs, and the new airport can be seen from the mountaintop along with a few mountains of Parnitha to its northwest, Penteli to its north, and Aegaleo to its west. The valley areas that creates the lowest passes are to the south and one further south.