Kastos
| Kastos Καστός | |
|---|---|
| Coordinates: 38°34′N 20°55′E / 38.567°N 20.917°E | |
| Country | Greece | 
| Administrative region | Ionian Islands | 
| Regional unit | Lefkada | 
| Municipality | Lefkada | 
| Area | |
| • Municipal unit | 5.901 km2 (2.278 sq mi) | 
| Highest elevation | 142 m (466 ft) | 
| Lowest elevation | 0 m (0 ft) | 
| Population  (2021) | |
| • Municipal unit | 40 | 
| • Municipal unit density | 6.8/km2 (18/sq mi) | 
| Time zone | UTC+2 (EET) | 
| • Summer (DST) | UTC+3 (EEST) | 
| Postal code | 300 19 | 
| Area code(s) | 26460 | 
| Vehicle registration | EY | 
Kastos (Greek: Καστός) is a Greek island and a former community east of the island of Lefkada, Ionian Islands, Greece. Since the 2011 local government reform it is part of the municipality Lefkada, of which it is a municipal unit. Until 1974, when it became part of the Lefkada Prefecture, the island was administered under the Cephalonia Prefecture (Ithaca province). The nearest island is Kalamos, with a deep channel between them; the mainland is approximately 5 kilometres (3 miles) to the northeast in Aetolia-Acarnania.