Municipalities range in population from Tallinn with 427,500 inhabitants to Ruhnu with 68.
[1] Previously, as over two-thirds of the municipalities had a population of under 3,000, many of them found it advantageous to co-operate in providing services and carrying out administrative functions.
After the administrative reform was completed in October 2017, there are total of 79 municipalities, 15 of which are urban and 64 rural.
The council (volikogu) is a representative body elected by the residents of a municipality for a term of three years.
It is headed by a mayor (linnapea in towns, vallavanem in parishes), who is appointed for a four-year term.