Diomea or Diomeia (Ancient Greek: Διόμεια) was a deme of ancient Attica, located in the city of Athens, both within and outside the walls of Themistocles, in interior portion included the eastern sector of the city, and the external portion contained the Cynosarges.
According to the legend the deme was founded by some citizens of Collytus and Melite, whose head was Diomus, worshiper and perhaps lover of Heracles.
After the death of the demigod, Diomus offered him a sacrifice but a white dog disturbed the event, stealing the sacrificial meats and leaving them far away.
[3][4] This shrine was associated with a gymnasium in which the illegitimate youth or those with only one Athenian citizen parent studied.
The deme, whose external part developed outside the walls of Athens, was not of a large extent, being bordered by Alopece which was 11 or 12 stadia from the city .