Argostoli (Greek: Αργοστόλι, Katharevousa: Αργοστόλιον) is a town and a former municipality on the island of Kefalonia, Ionian Islands, Greece. Since the 2011 local government reform it is part of the municipality Kefalonia, of which it is a municipal unit. It has been the capital and administrative centre of Kefalonia since 1757, following a population shift down from the old capital of Agios Georgios (also known as Kastro) to take advantage of the trading opportunities provided by the sheltered bay upon which Argostoli sits. Argostoli developed into one of the busiest ports in Greece, leading to prosperity and growth. The 2011 census recorded a population of 10,633 in the Argostoli municipal unit. Its largest towns are Argostóli (pop.