A city on the peninsula of Akte whose exact location is not known. It is likely, however, that it lay on the S coast near the monastery of Xiropotami. According to Herakleides (FHG II p. 222, fr. 31) it was founded by the Chalkideans. The city makes its first appearance in the Athenian Tribute Lists in 434-433 (ATL I 464).
Historically, little is known of the activities of the city as it seems to have been dominated by its more powerful neighbors, either Dion or Thyssos. During the first years of the Peloponnesian War Kleonai was on the side of the Athenians but shifted alliance to Brasidas in the winter of 424-423 (Thuc. 4.109). It was apparently regained for Athens by Kleon. Its loss in power and significance is indicated by the sharp drop in tribute from 500 drachmai (from 434-433 to 429-428) to only 100 in the year 421. After 421 the only references to Kleonai are geographical.
No excavations have been carried out in the area and archaeological exploration is not permitted on the peninsula now occupied by the monasteries of Mount Athos. Ancient sources, however, clearly place it on the Akte peninsula (Hdt. 7.22; Strab. 7.331, fr. 33, 35; Scyl. 66; Mela 2, 30; Plin. HN 4.37) and from the order of listing of sites in the area it is likely that it lay on the S coast. Although there are no extant remains which would conclusively fix its position, Demitsas' report of certain remains of ancient construction near the monastery of Xiropotami suggest that area as a possible site. (S. G. MILLER) Wikidata ID: Q17625411
Info: Princeton Encyclopedia
(Princeton Encyclopedia of Classical Sites, from Perseus Project)