Schoenus (also spelled Schoinous; Ancient Greek: Σχοινοῦς) was a port-town on the Saronic Gulf in ancient Corinthia, located on the Corinthian Isthmus. It was the only town on the Isthmus in ancient times.
Situated at the narrowest part of the Isthmus, Schoenus served as the port of the Isthmian sanctuary (the Sanctuary of Poseidon at Isthmia). It was the place at which goods not intended for the Corinthian market were transported across the Isthmus by means of the Diolcos—a paved trackway used to drag ships and cargo overland between the Saronic and Corinthian Gulfs, bypassing the dangerous circumnavigation of the Peloponnese.
The site of Schoenus is located in the modern village of Kalamaki, in the Peloponnese, Greece. The harbour is exposed to the east and south-east. The remains of the ancient town are sparse, indicated by a few fragments of Doric columns. The Isthmian sanctuary lies rather less than a mile (approximately 1.6 km) southeast of Schoenus.
The Roman geographer Pomponius Mela referred to the town as Portus Schoenitas.
The primary ancient source for Schoenus is Strabo (Geographica VIII, p. 380).
