Municipalities in Ontario
Ontario has 3 types of municipalities:
Upper-tier: a municipality of which two or more lower-tier municipalities form part for municipal purposes. Often referred to as "region".
Lower-tier: a municipality that forms part of an upper-tier municipality for municipal purposes.
Single-tier: a municipality, other than an upper-tier municipality, that does not form part of an upper-tier municipality for municipal purposes.
Durham Regional Municipalities