Territorial authorities are the second tier of local government in New Zealand, below regional councils. There are 67 territorial authorities: 13 city councils, 53 district councils and the Chatham Islands Council. District councils serve a combination of rural and urban communities, while city councils administer the larger urban areas. Five territorial authorities (Auckland, Nelson, Gisborne, Tasman and Marlborough) also perform the functions of a regional council and thus are unitary authorities. The Chatham Islands Council is a sui generis territorial authority that is similar to a unitary authority.