The administrative division of Denmark based on counties was in effect from 1662 to 2007.
After that only 5 regions apply.
For genealogy purposes you should note that the county board structure applied for this Ancestry forum is based on a short lived county division that was in effect from 1970 to 2007 only. And it’s not very useful, as Danish genealogy resources are based on the old stable county division valid until 1970. That included about 24 counties with the 4 counties of Northern Schleswig and the one of the Faroe Islands.
Only minor changes occurred from 1662 to 1970.
The problem is that when someone posts in a county board on this forum, the board name will not necessarily be related to the Danish archive structure. For some counties (Copenhagen Frederiksborg, Bornholm etc.) it doesn’t matter much. However, for other counties it may be directly misleading. Most genealogist refer to the old county structure.
To avoid misunderstandings my a advice would be to post directly in the “General” board unless you are looking for someone from the Copenhagen area or Bornholm.
When you refer to a county in your text my advice would be to use this division:http://www.dis-danmark.dk/kort/kort.htm
Note the counties has a substructure with parishes that opens with a click of the mouse.