Strabane had a population of 13,172 at the 2011 Census. It lies on the east bank of the River Foyle and is roughly midway from Omagh, Derry and Letterkenny. The River Foyle marks the border between Northern Ireland and the Republic of Ireland. On the other side of the river (across Lifford Bridge) is the smaller town of Lifford, which is the county town of County Donegal. The River Mourne flows through the centre of the town and meets the Finn to form the Foyle River. A large hill named Knockavoe, which marks the beginning of the Sperrin Mountains, forms the backdrop to the town.