Argostoli is a town and a municipality on the island of Kefalonia, Ionian Islands, Greece. Since the 2019 local government reform it is one of the three municipalities on the island. It has been the capital and administrative centre of Kefalonia since 1757, following a population shift down from the old capital of Agios Georgios 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 municipality has an area of 377.0 km² and the municipal unit has an area of 157.670 km². The 2011 census recorded a population of 10,633 in the Argostoli municipal unit, and 23,499 in the municipality in its post-2019 extension. Its largest towns are Argostóli, Razata, Dilináta and Kompothekráta.