Belfast Lough is a long, wide and deep expanse of water, virtually free of strong tides. The inner part of the lough comprises a series of mudflats and lagoons. The outer lough is restricted to mainly rocky shores with some small sandy bays. The outer boundary of the lough is a line joining Orlock Point and Blackhead. The main coastal towns are Bangor on the southern shore (County Down) and Carrickfergus on the northern shore (County Antrim). Other coastal settlements include Holywood, Helen's Bay, Greenisland and Whitehead.