around 1,000 parish municipalities sognekommuner, being supervised by their county, and market city municipalities købstadskommuner, the latter numbering 86 (including Bornholm whose county as an exception supervised the county's six market city municipalities (of 21 in total)) and not being part of a county but being supervised by the Interior Ministry.

The reform was initiated from 1958 by the Interior Minister Søren Olesen, (1891-1973), a member of the Justice Party of Denmark.