Emathia (Greek: Ἠμαθία) was called the plain opposite Thermaikos Gulf when Kingdom of Macedon was formed. With this name was defined the area between the rivers Aliakmon and Loudias, which, because it was the center of the Kingdom was also called Macedonia. Emathia was one of the six earliest provinces of Kingdom of Macedon and was boarded on the west with Orestis, on the north was separated from Bisaltia by river Loudias and on the south was separated from Pieria by river Aliakmon.
According to Solinus and Justin, Emathia was named after the Samothracian king Emathion and not after the local Emathus. The etymology of the name has been related to Homeric Greek amathos and êmathoessa (< PIE *samadh) 'sandy land', i. e. the coastal, swampy land around Axius river, in contrast to mountainous Macedonia, probably also intended as 'meadow land' (cf. PIE *mē-2, *m-e-t- 'to mow, to reap').
|“||but Hera darted down and left the peak of Olympus; on Pieria she stepped and lovely Emathia, and sped over the snowy mountains of the Thracian horsemen, even over their topmost peaks, nor grazed she the ground with her feet; and from Athos she stepped upon the billowy sea, and so came to Lemnos, the city of godlike Thoas||”|
The Homeric name was renewed mainly in Roman times and Ptolemy mentions some cities of Emathia. In Nonnus, Dionysiaca 48.6 Typhoeus having stript the mountains of Emathia, he cast the rocky missiles at Dionysus. In Ovidius, Metamorphoses 5.313 the daughters of Pierus say: we grant Emathia's plains, to where uprise Paeonia's peaks of snow. The Emathian or Emathius dux is a frequently used name by Latin poets for Alexander the Great, as in Milton, the Emathian conqueror . Strabo  relates that what is now called Macedonia was in earlier times called Emathia but since Homer, the earliest source considers Emathia only a region next to Pieria, Strabo's reference should be interpreted in the Roman era context of Emathia's name reviving. The same stands for Latin writers who name Thessaly as Emathia ; Macedonia (Roman province) included Thessaly. In 12.462 of Metamorphoses, an Emathian Halesus is killed by the centaur Latreus and in Catullus 64. 324, Peleus is Emathiae tutamen (protector).
Polybius (23.10.4) mentions that Emathia was earliest called Paeonia and Strabo (frg 7.38) that Paeonia was extended to Pieria and Pelagonia. According to Hammond the references are related to Bronze Age period before the Trojan War.
The most important towns of Emathia were: