Mount Olympus was home to the majority of the pantheon of Greek gods. Other Greek gods lived on the Earth, in the oceans, in the sky, in Tartarus or in Elysium.
Even the gods who lived on Mount Olympus, considered the tallest mountain in the world, occasionally came down from their mountain and meddled in the affairs of other gods and the affairs of mortals. Gods who were in charge of specific parts of the world, such as Poseidon who ruled the sea, lived in the areas in which they ruled. Hades, god of the Underworld, resided in Tartarus, or Hell.