The archaeological site and museum of Isthmia are located in the picturesque village of Kyra vrisi at the Isthmus of Corinth in the Municipality of Loutraki-Perachora-Haghii Theodori on the coast of the Saronic Gulf. The museum was built in 1970 next to the archaeological site of the Sanctuary of Poseidon / Neptune, one of the four Pan-Hellenic sanctuaries, where sports and music competitions were held in ancient times. The museum opens its doors to the public in 1978 and is renewed between 2005 and 2007.
In the Archaeological Museum of Isthmia are exhibited the finds that come from the excavations carried out by the American Archaeological School of Athens both at the site of the Sanctuary of Poseidon of Isthmia, both in the area of the ancient port of Kechrees, but also in the area of Isthmo. Among the most important finds in the museum are the stained glass windows (stained glass paintings) brought to light during the excavations of the ancient port of Kechrees.
The main areas that the visitor can admire in the archaeological site and museum of Isthmia are:
- the temple of Poseidon / Neptune from the Archaic period to the Roman period
- “Palaimonion”, a sanctuary from the Roman period dedicated to Palemone / Melicerte, the child to whom the temple was dedicated
- the stadium’s foundations
- the theater in which, according to sources, the emperor Nero was among the competitors in a musical and poetic competition
- The Roman Baths, homage of Herodes Atticus to the Sanctuary.