An upper-tier municipality is made up of 2 or more lower-tier municipalities. Municipal responsibilities set out under the Municipal Act and other Provincial legislation are split between the upper-tier and lower-tier municipalities. A lower-tier municipality forms part of an upper-tier municipality. Municipal responsibilities set out under the Municipal Act and other Provincial legislation are split between the upper-tier and lower-tier municipalities. A single-tier municipality doesn't form part of an upper-tier municipality and assumes all municipal responsibilities set out under the Municipal Act and other Provincial legislation. Territorial districts are geographic areas in northern Ontario. They are described in the Territorial Division Act, and are composed of municipalities, geographic townships and un-surveyed territory.