Dublin is the largest city in Ireland and the capital of the Republic of Ireland. It is located near the midpoint of Ireland's east coast, at the mouth of the River Liffey and at the centre of the Dublin Region. Founded as a Viking settlement, the city has been Ireland's primary city for most of the island's history since medieval times. Today, it is an economic, administrative and cultural centre for the island of Ireland, and has one of the fastest growing populations of any European capital city