Nafplio is a seaport town in the Peloponnese in Greece that has expanded up the hillsides near the north end of the Argolic Gulf. The town was an important seaport held under a succession of royal houses in the Middle Ages as part of the lordship of Argos and Nauplia, held initially by the de la Roche following the Fourth Crusade before coming under the Republic of Venice and, lastly, the Ottoman Empire. The town was the capital of the First Hellenic Republic and of the Kingdom of Greece, from the start of the Greek Revolution in 1821 until 1834. Nafplio is now the capital of the regional unit of Argolis.
Nafplio is situated on the Argolic Gulf in the northeast Peloponnese. Most of the old town is on a peninsula jutting into the gulf; this peninsula forms a naturally protected bay that is enhanced by the addition of man-made moles. Originally almost isolated by marshes, deliberate landfill projects, primarily since the 1970s, have nearly doubled the land area of the city.