National Road 42 (Greek: Εθνική Οδός 42) is a highway in northwestern Aetolia-Acarnania and in Lefkada, Greece.

[1] It links the town of Lefkada with the Greek National Road 5 (Antirrio - Arta - Ioannina) in Amfilochia, passing through the town of Vonitsa.

The eastern part of the GR-42, between Amfilochia and Vonitsa, runs along the southern shore of the Ambracian Gulf.

A drawbridge form the connection of the island of Lefkada to the mainland.

The GR-42 passes through the following towns (ordered from west to east):