Dublin is both the largest city and the capital 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. Dublin is one of the constituent cities in the Dublin-Belfast corridor region which has a population of just under 3 million.